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HomeMy WebLinkAbout136ORDINANCE NO. 136 AN ORDINANCE OF THE CITY COUNCIL OF THE TOWN OF LOS ALTOS HILLS PROVIDING FOR THE SANITARY DISPOSAL OF SEWAGE, DECLARING VIOLATIONS THEREOF TO CONSTITUTE PUBLIC NUISANCE, REPEALING ORDINANCES AND PORTIONS THEREOF IN CONFLICT THEREWITH, AND PROVIDING FOR PENALTIES FOR VIOLATION. THE CITY COUNCIL OF THE TOWN OF LOS ALTOS HILLS DOES HEREBY ORDAIN AS FOLLOWS: SECTION 1. For purposes of this ordinance, the following terms, phrases, words and their derivations shall have the meaning given herein. When not inconsistent with the context, words used in the present tense include the future, words in the plural number include the singular number, and words used in the singular number include the plural number. The word "shall" is always mandatory and not merely directory. (a) "Health Officer" Health .Officer shall mean the Santa Clara County Health Officer, his assistants, or authorized deputies acting as Health Officer of the Town of Los Altos Hills. (b) "Building Inspector" Building Inspector shall mean the Building Inspector or his assistant(s) employed by the Town of Los Altos Hills. (c) "Franchised Pumper" Franchised Pumper shall mean the duly franchised firm or firms selected by the Town of Los Altos Hills to perform septic tank pumping. (d) "Percolation Rate" Percolation rate shall mean that rate expressed in minutes per inch as determined by percolation tests made in accordance with procedure described in Town Standards. (e) "Sanitary Waste" Sanitary Waste includes, but is not limited to, the discharge from toilets, bathtubs, lavatories, dishwashers, washing machines, and any and all other fixtures connected to the building plumbing system. (f) "Town Standards" Town Standards shall mean those standards relating to individual sewage disposal system design, construction and/or maintenance as approved by the Health Officer and as adopted by Resolution of the Town Council. (g) "Failing System" A failing system is one in which all or any of the following conditions are observed: n 1. Surfacing of water in the area occupied by the private sewage disposal system. (When such surfacing occurs, owner may elect to demonstrate influence of waters other than of sewage origin and correct by submission of engineering report and installation of sub -surface drainage system pursuant to Section 6.) 2. Surfacing of water in adjacent or other areas near the sewage disposal system area where it can be demonstrated that liquid from the system is present. These areas include those where ownership or occupancy is different from that on which the system is located. 3. Failure of plumbing fixtures within the structure served by the system to properly drain. This does not include a failure of the plumbing system. 4. Saturation of the drainfield during a dry season as evidenced from inspection wells. SECTION 2. It shall be unlawful to maintain, or use, any residence, place of business, or other building or place where persons reside, con- gregate, or are employed which is not provided with a water -flush toilet and with the discharge of all sanitary waste to a sewage system approved by the Health Officer. When judged permissible by the Health Officer, a privy or other form of toilet which meets the requirements of construction and maintenance hereinafter described may be used in lieu of the water - flush toilet. SECTION 3. All existing buildings where persons reside, congregate or are employed shall be required to be connected to an approved public sewer when such sewer is reasonably available except when the existing means of sewage disposal is functioning in conformance to the requirements of this ordinance and to the Town Standards and to the satisfaction of the Health Officer. SECTION 4. It shall be unlawful for any person to construct or main- tain any spetic tank, sewage treatment works, sewer pipes or conduits, or other pipes or conduits for the treatment or discharge of sewage or impure waters or any matter or substance offensive injurious or dangerous to health, whereby they shall do any of the following: '(a) Overflow any lends whatever; (b) Empty, flow, seep, drain into or affect any springs, streams, rivers, lakes or other waters within the Town of Los Altos Hills. -2- SECTION 5. Livery residence, place of residence, or other building or place where persons congregate, reside or are employed, which is not connected to a public sewer. system shall be provided with a private sewage disposal system, said disposal system to be built or rebuilt, constructed, altered or reconstructed or repaired, and maintained in such a manner as to meet the requirements of this ordinance and in accordance with Town Standards as adopted by Resolution of the Town Council. (a) New Construction: The minimum system for any premise shall include a two compartment septic tank of 1,520 gallons water capacity measured at flow line, a diversion box and a disposal field consisting of gavel filled leachir� nch system.The disposal field shall be installed so as to form twoindependent sections each containinE half of the total lengrth of trench. Additional area must be kept available, on each premise on which the sewage disposal system is proposed to provide for the expansion of the disposal field by at least 100%. This area must be indicated on the p1a_n. The length of leaching trench required shall be determined from the stabilized percolation rate performed as outlined in the town standards and in accordance with the following values: Length of Stabilized Percolation Rate Gravel Filled Trench Not over 60 min. per inch - u Y4400 feet ry Not over 90 min. per inch but greater than 60 min. per inch 600 feet Not over 120 min. per inch but greater than 90 min. per inch 800 feet When the stabilized percolation rate is in excess of 120 minutes per inch individual sewage disposal systems will be approved only if the total lot size is 3.0 acres or greater, except that special consideration may be given to premises having percolation rates greater than 120 minutes per.inch where detailed soil analysis studies are presented. Each of the two independent sections of the installed disposal field shall receive the entire effluent flow of the septic tank for a 6 month period. At the end of this period the gates in the diversion box shall be so manipulated that the section of the disposal field previously lying idle will receive the total septic tank effluent flow for the ensuing six month period. -3- Alternate systems will be considered by the Health Officer upon request of the applicant. Requirements for submission of said alternative plan are outlined in the Town Standards. (b) Existing Systems: Owners or residents on premises with existing private sewage disposal systems which are failing or where failure may appear imminent and where a public sewer is not readily available shall repair, modify and/or expand their system upon order of the Health Officer. The modification and/or expansion shall be such as may bring about correction of the failure or elimination of the imminent failure. The alterations to such a system may consist of the addition of a filter preceding the disposal field and/or additional leaching lines together with a diversion box. There may also be added a dosing tank equipped with automatically controlled pump or siphon installation discharging to the filter or to the diversion box. The diversion box provides for the dosing of alternate sections of the disposal field for an extended period of time. .The enlarged disposal field resulting from the previously existing field together with the additional leaching lines shall be divided into two or more sections, each of which shall be dosed for an extended period of time while other section.(s) not being dosed are 'resting. SECTION 6. Sub-Surfacg Drainage: The Health Officer may require the installation of sub -surface drainage on any premise on which a private sewage disposal system is proposed or on which there is an existing sewage disposal system which is failing or in which failure is imminent. Prior to installation of the drainage system, the Health Officer may require the owner or resident of the premise to submit a report showing nature and extent of sub -surface water movement and method of draining. Such report shall be prepared by a registered Civil Engineer. SECTION 7. Except as otherwise stated in this ordinance, minimum standards formaintenanceand/or construction for altering or expanding private sewage disposal plants for septic tank, drains, dosing tank, filter bed, diversion box and disposal field and leach lines shall be as contained in Town Standards as approved by the Health Officer and as adopted by Resolution of the Town Council. _4_ SECTION 8. It shall be unlawful to construct, maintain or operate as part of aprivate sewage disposal system a leaching sump exceeding six feet in depth except with the specific approval and in accordance with requirements established by the San Francisco Bay Regional Water Quality Control Hoard. SECTION 9. It shall be unlawful to use a cesspool for the disposal of sewage. SECTI_GN 10. It shall be unlawful to drill, construct, maintain or operate a sewer well. SECTION 11. It shall be unlawful for any person, firm or corporation to construct, build, or rebuild any residence, place of residence, or other building or place where persons congregate, reside or are employed which is not to be connected to an approved public sanitary sewer without first submitting plans of the means of sewage disposal to the Health Officer, and obtaining a permit therefor as herein provided. The application shall be prepared by a registered Civil Engineer and shall include a plot plan of the premises showing overall topography and surface drainage direction; specific location of septic tank; leaching field and other finished elevations of structures and leaching field; a. plan and elevation v-:ews of all structures including leaching field, giving all dimensions; and such other pertinent information as Health Officer may require. If the application is prepared and the work proposed both in conformance with the requirements of this ordinance and with the Town Standards, the Health Officer shall issue the septic tank permit. Every applicant for a permit shall pay to the Health Officer for each permit issued and at the time of issuance a fee of 9110.00 for each sewage. disposal system. SECTION 12. It shall be unlawful for any person, firm or corporation to alter, repair, expand, or otherwise modify an existing sewage disposal system without first submitting plans of the proposed work to the Health Officer, and obtaining a permit therefor as herein provided. The application shall include a plot plan of the premise showing overall topography and surface direction, description of existing system and details of proposed alteration or modifications showing all dimensions and such other pertinent information as the Health Officer may require. The Health Officer may -5- require preparation of this application by a registered Civil Engineer. If the application is prepared and the work proposed both in conformance with the requirements of this ordinance and with the Town Standards the Health Officer shall issue the septic tank permit. Every applicant. for a permit shall pay to the Health Officer for each permit issued and at the time of issuance a fee of $10.00 for each sewage disposal system. SECTION 13. The Town Engineer shall review all plans for proposed sewage disposal installations and all plans for proposed alterations.,, improvements or exapnsions of,existing sewage disposal installations and shall make all necessary site inspections to determine conformance with minimum Town Standards. The Town Engineer shall report his deter- minations to the Health Officer. After issuance of permit by the Health Officer the Town Engineer shall conduct such inspections on premises as are necessary to assure carrying out of proposed construction in accordance with plans approved by the Health Officer. The Health Officer may elect to make any or all of the reviews and inspections referred to in this section in lieu of the Town Engineer. SECTI_O_N 14. The applicant for a septic tank permit for new construction or for existing system modification or expansion shall pay to the Town plan review and field inspection fees in the same manner and in the same amount as other building fees. The fees shall be those specified from time to time by Resolution of the City Council. SEC_T_ION 15. No building permit shall be issued for any building which is not to be connected to an approved public sanitary sewer, without the written approval of the Health Officer of the proposed means of sewage disposal for said building. SECTION 16. No Certification of Occupancy shall be issued for any building which is not connected to an approved public sanitary sewer without the written approval by the Health Officer of the means of sewage disposal for said building. SECTION _17. All sewage disposal system failures shall be reported within 10 days of their occurrence to the Town of Los Altos Hills by the owner or resident. SECTION 18. All private disposal systems shall be pumped, for maintenance purposes,at least once every four (4) years. All pumping must be done by a franchised pumper. Each pumper shall report to the Health Officer all pumping made during the month. Each franchised pumper shall be registered with the Health Officer and shall utilize a disposal point or site approved by the Health Officer. SECTION 19.- Each resident of a premise, or the owner if the premise is vacant,. -having a sewage disposal system incorporating a pump, siphon and/or diversion box shall inspect said pump, siphon and/or diversion box at intervals not to exceed six months to determine operating condition, perform necessary maintenance and to alternate gates in the diversion box. SECTION 22. Every house sewer shall end in a wye branch connecting to the house drain; the wye shall be brought up to ground level and closed by a cap, to be available as a cleanout. _SECTIO_N 21. It shall be the duty of the City Manager, on recommendation of the Health Officer to enforce the provision of this ordinance, and in the performance of this duty, the City Manager, Health Officer, or any duly authorized agent of the foregoing,•is hereby authorized to enter at any reasonable hour any premises as may be necessary in the enforcement of this ordinance and to make such investigation including taking of samples and conducting of dye tests. Any person, firm or corporation who violates or refuses or fails to comply with any of the provisions of this ordinance shall be guilty of a misdemeanor and shall be punished upon conviction by a fine of not less than ((25.00, not more than $500.00, or by imprisonment in the County Jail for not more than six (6) months or by both such fine and imprisonment. SECTION L. Every violation of this ordinance shall constitute a public nuisance and be subject to abatement as such. SECTION 23. Each ordinance or portion thereof in conflict with this ordinance is hereby repealed.. - SECTION,24_ If any section, subsection, paragraph, sentence, clause or phrase of this ordinance is for any reason held to be unconsitituional -7- or invalid, such decision shall not affect the validity of the remaining portion of this ordinance. The Council of the Town of Los Altos Hills hereby declares that it would have passed this ordinance and each section, subsection, paragraph, sentence, clause and phrase thereof irrespective of the fact that any one or more sections, subsections, paragraphs, sentences, clauses or phrases be declared unconstitutional or invalid. SECTION 25. This ordinance shall not be construed as imposing upon the Town of Los Altos Hills any liability or responsibility for damage resulting from the defective construction of any sanitary disposal system as herein provided, nor shall the Town of Los Altos Hills or any official or employee thereof be held as assuming any such liability or responsibility by reason of the inspection authorized thereunder. SECTION 26. This ordinance shall be posted in three (3) public places in the Town of Los Altos Hills and shall become effective thirty (30) days following its adoption. SECTION 27. APPEALS. Any applicant aggrieved by a determination of any administrative official may appeal such determination to the Town Council -by filing a written notice of appeal with the City Manager within ten (10) days after receiving notice of the administrative official's determination. The City Manager shall then put the matter on the next open agenda for hearing at a regularly scheduled Town Council meeting. ++++++++++++++++ I HEREBY CERTIFY THAT the foregoing ordinance was introduced at a regular adjourned meeting of the City Council of the Town of Los Altos Hills on the 23rd day of May, 1968, and was thereafter, following the holding of a public hearing, pursuant to notice as required by law, at a regular meeting of said Council held on the 3rd day of June, 1968, passed and adopted by the following roll call vote: AYES: Councilmen Benson, Davey, Fowls, Helgesson, Mayor Aiken. NOES: None. ABSENT: None. APPROVED /s// WM. ROSS AIKEN Mayor, Town of Los Altos Hills M " ATTEST: _ /s/ DENNIS R. LAHR City Clerk Town of Los Altos Hills TOWN STANDARDS FOR PRIVATE SEWAGE DISPOSAL These standards are minimum standards intended to provide adequate facilities for sub -surface disposal of sewage under average usage and general conditions. Where proposed usage or known topographic, soil permeability, drainage or other physical features will produce conditions that are not average or general, these minimum requirements shall be exceeded as deemed necessary by the Health Officer. A. DEFINITIONS 1. Septic Taisc Disposal System: Septic tank disposal system shall mean any system for the private disposal of sewage or other liquid waste including but not limited to a septic tank and disposal fie -Lu. 2. Septic Tank: Septic tank shall mean a watertight tank designed to receive sewage or other liquid waste and to provide sedimentation and partial sludge digestion. 3. Disposal -Field: Disposal field shall mean a system of underground drain or leach lines laid in gravel lined trenches for the purpose of receiving effluent from the septic tank for percolation into the adjoining ground. 4. Diversion Box: Diversion box shall mean a structure designed to permit introduction of septic tank or filter effluent into alternate sections of the disposal field, so that one or more sections of the disposal field may undergo an extended resting period. 5. Dosing Chamber: Dosing chamber shall mean a watertight compartment or structure provided with float controlled automatic pump or auto- matic siphon designed to receive the effluent from the septic tank and fromwhicheffluent will be discharged intermittently in doses to either a filter or to the disposal field. 6. Filter: Filter shall mean a bed of graded filtering material through which septic tank effluent passes prior to its introduction into the disposal field. B. SEPTIC TANK DISPOSAL SYSTEM Each septic tank disposal system shall consist of the following components: (1) septic tank, (2) diversion box, and (3) disposal field. It may also include either or both of the following components: (1) dosing chamber, and (2) filter. No portion of the septic tank disposal system shall be located within 10 feet of a foundation, 10 feet of a property line, 10 feet of a swimming pool, or 100 feet of a water well, except that a septic tank may be located within 5 feet of a foundation. 1. Septic Tank: The septic tank shall be constructed of concrete or masonry units. Tanks shall have smooth finished walls and bottom at least 4 inches thick. When concrete blocks, other than approved interlocking blocks or precast masonry units are used, they shall be waterproofed, laid with cement mortar, and shall be reinforced with half-inch steel bars vertical and horizontal on two -foot centers. All hollow units shall be poured solid with cement mortar. The septic tank shall have a minimum water capacity of 1,500 gallons measured at flowline and shall be constructed with two compartments. The capacity of the second compartment shall be one-half of the capacity of the first compartment. The general configuration of the tank shall be as shown in Figure 1. Dimensions for tank capacities not shown or deviations from the dimensions shown must be approved by the Health Officer. The septic tank, and outlet and inlet connections, shall be watertight. The septic tank top may be of two layers of two-inch redwood board covered with building paper and at least 6 -inches of dirt to form a water -and odor seal. Concrete tanks with poured concrete covers need not be covered with a dirt seal. Each poured concrete cover shall have two manholes, one over the inlet and one over the out- let, each at least 22 inches in diameter, and with tight fitting lids. These lids shall be provided with iron U -bolts, or reinforcing rod handholds, to facilitate lifting. Inlet and outlet baffles may beof one -inch redwood board mortared into side wall notches. Vitrified clay septic tank tees or vitrified clay septic tank ells cast in place may be substituted for these inlet and outlet baffles. See Figure 1. 2. Disposal Field: In addition to the general limitations upon location of any portion of a septic tank disposal system, no portion of a disposal field shall be located in a filled ground area, or within 50 feet of any creek, drainage ditch bank or any cut slope bank below the elevation of the disposal field. Leaching lines may not be laid in existing or proposed paved surface areas or areas subject to vehicular traffic. The disposal field shall consist of leaching lines laid in gravel lined trenches. Leaching line tile shall be of clay, not less than 4 inches in diameter, not more than 12 inches long and shall be laid with 14" to 'Fi" openings at joints. Perforated, bituminous, plastic or other types of leaching line may be used when approved by the Health Officer. Leaching lines shall be laid no closer than 8 feet on centers. The total lineal length of trench shall be determined from subsurface soil analysis based upon observations of test borings and percolation tests. Boring requirements and percolation test procedure shall be as described in Sections 6 and %. Previous soil mantle shall extend for a depth of at least 3 feet below the proposed trench bottom. The water table shall not lie within three feet of the trench bottom. Required depth of trench shall be 6 feet. The Health Officer may permit modification of this depth. Trench width shall be not less than twelve inches and not more than eighteen inches except that all of the trench in any one private sewage disposal system shall be of the same width. The trench bottom shall be carefully excavated to level grade. Trench walls or those portions of trench walls which have been sealed by the excavating equipment shall be scarified to the satisfaction of the Health Officer prior to placing of gravel. The excavated trench shall be filled with 3/4" to 1%z" gravel from the bottom to the level of the base of the tile which shall be laid to grade. Gravel shall be added to a depth of 4 inches above the tile, covered with building paper to prevent clogging with earth and the remainder of the trench backfilled. There shall be at least twelve inches of backfill below finished grade of adjoining ground surface. -3- The backfilled trench should be well tamped and be over -filled with 4 inches to 8 inches of earth to prevent depressions due to settling of earth (trench line depressions may collect storm water, leading to premature saturation of the absorption field and possibly to trench washouts). Trucks and heavy grading equipment shall be excluded from the disposal area unless special provision is made to support the weight. See Figure 2. Sections of disposal fields located on hillsides at different elevations shall be separated by undisturbed earth dams at least 2 feet across at the ground surface. There shall be a pipe transfer from the terminus of the trench at one elevation to the inlet of the _trench at a lower elevation. - Section connecting lines or pipe transfers shall be 4 -inch tight -joint sewers with connections to the distribution tiles in adjacent sections or to -a drep box. The crown of the transfer shall be at least 2 inches below the top of the gravel. Transfer -lines shall be so constructed as to insure an undisturbed block of earth between sections. The trench connecting the transfer -pipe and the preceding asborption section shall be dug no deeper than the top of the soil gravel interface. The transfer line shall rest on undisturbed earth and backfill shall be carefully tamped. Inspection wells consisting of four inch pipe placed vertically in the trench from the bottom to the surface of the ground and provided with a cap or plug shall be placed at the terminus of each trench or/and at such other points as will make possible a check of the water table elevation within the trench at the inspection well points. These sampling wells shall be adequately marked to permit ready location and provide protection from damage. 3. Dosing Chamber: The dosing chamber where employed shall be constructed of concrete or masonry units and may be an independent structure or a third compartment of the septic tank structure. It shall have smooth finished walls and bottom at least 4 inches thick. When concrete block or other than approved interlocking blocks or masonry units are used, -4- they shall be waterproofed, laid with cement mortar and shall be reinforced with half inch steel bars vertical and horizontal on two foot centers. All hollow units shall be poured solid with cement mortar. The dosing chamber top may be of two layers of two-inch redwood board covered with building paper and at least 6 inches of dirt to form a water and odcr,seal. Concrete tanks with poured concrete covers need not be hovered with a dirt seal. Each poured cover shall have two manholes, one over the inlet and one over the outlet, each at least 22 inches in diameter and with tight fitting lids. These lids s,,i i be fitted with iron U -bolts or reinforcing rod handholds to facilitate lifting. The dosing chamber shall be equipped with an automatic float controlled submersible pump having a capacity of at least 15 gallons per minute or an automatic siphon at least 3 inches in size. The pump control shall be set to start the pump at a water level of 6 inches below the inlet and to shut the pump off at a water level of 6 inches above the bottom of the tank. The dosing tank top or manhole covers shall extend to grade and be constructed to give easy access to the dosing tank and to permit periodic inspection and maintenance. The dosing chamber if located between the septic tank and the leaching field shall have a minimum capacity equal to the approximate void volume of the leaching field or section of leaching field to which it discharges. The dosing chamber if located between the septic tank and a filter and used to dose the filter shall have a minimum capacity not less than 400 gallons. 4. Filter: The filter, if used, shall be contained by side walls con- structed of concrete or masonry units or irrigation heart grade redwood. The minimum capacity shall be based upon the estimated maximum daily domestic water usage, and shall not be less than 400 gallons per day per residence. The filter media shall be selected for durability and effective surface area. An application for a proposed filter shall be accompanied with supporting design data and detailed specifications. -5- 5. Diversion Box: The diversion box shall be located at the beginning of the disposal field and shall be connected to the septic tank by a tight line placed on undisturbed soil or otherwise installed to minimize the danger of breakage or displacement. The box shall be kept to a minimum size necessary to accommodate the inlet and the outlets but not less than 18 inches in either width or length. The box shall extend to the surface of the ground and be fitted with an easily removable lid to permit periodic inspection and alternation of outlet in use. There shall be at least two outlets each connected to independent sections of the disposal field. Each outlet shall be constructed to permit opening or closing of a gate so that only one outlet will be in use at any particular time. 6. Boring Requirements: There shall be at least one test boring at each proposed disposal field site. These borings shall be to rock, hardpan, water or to a maximum depth of nine feet. 7. Percolation Tests: There shall be at least three percolation tests at the site of each proposed disposal field. Tests shall be made in holes having a diameter of not less than 8" or more than 10". Test holes are not to exceed 48" in depth. Wall surfaces in holes may be scarified if there is sealing during digging. Test holes shall be flooded at least once 24 hours before the per- formance of the test. The Health Officer may require additional presoaking. The initial test reading shall be at a depth of 12 inches below grade. Successive readings shall be made at hourly intervals until at least two successive falls are equal. If the fall at any reading exceeds one-half inch, the water level in the hole shall be brought up to the 12 inch mark before the start of the next hourly interval. The Health Officer may specify other test reading intervals. 8. Standards for Alternate Private Sewage Disposal Systems: Applications for permits to construct, maintain and operate private sewage disposal systems, using alternate methods or designs, will be considered by the Health Officer upon request by the applicant. Each application shall be submitted with 5 copies of plans and specifications and engineering data. Additional information and supporting data shall be furnished upon request of the Health Officer. 160 -•k—s•--Yw.,m r. u..ra.Y w.ir., mxl..., r..er,.,e •. _.. _.. ... —�--- r Jj C hli rrj I _ _ v M''1ry'tm�r[_1 Au�ll,.1•�[J_[YJi�+.1+-1-1R1_ - i � ri�1v� - ANL..I uuIJI I �� -i firs 1^'� ('���`� • • . . 3(p1µ lLnA .IOI Yl1'/ (O"'�� aSi 8 i 5 1 <; 7&-- to ,5 4 _[5 . _ badfill(eanh) I4 fe I/I•Gry oC/ J v -moi :'cgnY' . _ Iw .�Y -,'�% • Ity �� Ynrrcme�Soild�n� Wie.� I- i]•Jm�� . D/✓Ar5/O7. c. hl joinla�-hr's-...+r L;,' ly,�': . .� J{ I( JI�:�...t 1--. r-fBax•. .. -• —__- c.�-O F• eY =i=u r r [, I1�,'� m.lope Iw. ..:N'g` '�) > ry $ 3�*_ '• <� }�./ • ��`I mdivvA.d .erth bv.¢h /2 B" ' Idarol, F4' dayday Ht ' ep.n jdnred w.rr plpo v J SANTA CLARA COUNTY HEALTH DEPARTMENT DIVISION OF SANITATION 270 Grant Avenue Palo Alto, Calif. 94306 PERCOLATION TEST INSTRUCTIONS As Required in the Town of Los Altos Hills (Ordinance No. 136) There shall be one test boring and at least three percolation test holes at the site of each proposed drainfield. The location of these holes and the boring shall be determined by the Health Department. 1. "The test boring shall not be less than 8 inches in diameter and be drilled to hard pan, rock, water, or a maximum of 9 feet. 2. Each percolation test hole must be 8 to 10 inches in diameter and drilled to a depth of 48 inches. Wall surfaces in the percolation test holes should be scarified if there is sealing during digging. All possible loose earth should be removed from the holes. 3. Percolation test holes (not the test boring) shall be flooded to a level 12 inches below surface once at least 24 hours before the performance of the test. The Health Officer may require additional pre-soaking. 4. After the test holes have been pre-soaked, a heavy gauge nail shall be inserted into the side wall of each hole approximately 12 inches below ground level. 5. Enough water must be on hand (truck, barrel, or hose) the day of the test to completely fill each hole at least 3 times. This does not include the water used for pre-soaking. AT LEAST 48 HOUR PRIOR TO DESIRED TEST DATE, CONTACT THE DISTRICT SANITARIAN (321-3141, extension 281) FOR AN APPOINTMENT. "Pervious soil mantle shall extend for a depth of at least 3 feet below the proposed trench bottom. The water table shall not be within 3 feet of the trench bottom." (Excerpt from Town Standards for Private Sewage Disposal).