Rules and Regulations for Establishing Minimum Domestic Water System
Requirements Pursuant to Marin County Code Section 7.28

Source Yield

The minimum sustained yield of water from a source or sources shall not be less than the following:

Minimum Storage capacity shall not be less than the following:

For uses other than that specified above the minimum yield and storage requirements shall be based on estimated consumption as approved by the "Health Officer." All sources shall be perennial.

Test Method

Gravity Fed Source - Flow from the source shall be measured by recording the time it takes to fill a container of known volume (minimum size (2) two gallons). The average of three such measurements taken within (1) one hour shall comprise a test. At least (3) three tests shall be taken each spaced at least 6-days apart. Testing of a horizontal well shall not be performed until at least 30 days after the well has been drilled.

Pumped Source

Step 1. Commence the test no sooner than 7-days after development of the well. Record the time and the initial level of the water in the well prior to start of pumping.

Step 2. Start pumping at a rate of 10 GPM, or more, until a 3-day minimum yield is pumped from the well, or until the well is "pumped dry".*
* "Pumped Dry" is the point at which the pump starts pumping air, thus reducing the pumping rate.

• If a 3-day yield is obtained without "pumping dry" skip to Step 5.
• If the well is "pumped dry" continue to Step 3.

Step 3. Record the time at which the well is "pumped dry" and the new pumping rate at which the pump continues to operate.

Step 4. Continue pumping and record the pumping rate at one hour intervals commencing at the time in Step 3, until the same reduced pumping rate is obtained on 3 consecutive hours.

• If the 3 consecutive hourly readings are less than the minimum yield required, the yield is inadequate.
• If the 3 consecutive hourly readings are equal to or greater than the minimum allowable yield and a 3-day yield was pumped from the well, continue to Step 5
.
• If the consecutive hourly readings are equal to or greater than the minimum allowable yield, but a 3-day yield was not pumped from the well, continue pumping until this total 3-day yield is      obtained, then continue to Step 5.

Step 5. End pumping and record the time and the elevation of the water level at the completion of pumping.

Step 6.   72 hours after the time recorded in Step 5, measure and record the water level in the well.

• a.  If the is a 100% recovery of the initial water level at 72-hour measurement, the well yield is adequate.
• b.  If the above recovery is not obtained for the well, this yield is inadequate.
• c. Test Results - The results of the yield tests shall be recorded on the forms provided by the "Health Officer." All applicable blanks on the forms shall be filled out.
• The yield of a gravity fed source shall be the lowest of the (3) three tests. The yield of a pumped source shall be the pumping rate established by the "3-day yield pumping tests."

Seasonal Timing of Tests

The yield testing shall be performed during the dry season (July 15 to October 1, unless the "Health Officer" expands this time limit due to lack of precipitation). Testing outside of the dry season may be allowed if sufficient data as approved by the "Health Officer" is submitted which correlates the actual test results with dry season results to establish actual sustained yield at the driest season.

Qualifications of Persons Making Tests

Yield tests shall be made only by State Licensed Well Drilling Contractors, General (Class A License) Contractors, Civil Engineers, or Geologists, except where a gravity fed source will supply (1) one single family dwelling, the test may be made by the property owner. Verification by a representative of the "Health Officer" may be required.

Source Setbacks

Water Quality

The water shall meet the physical, chemical and bacteriological standards of the State Department of Public Health and the US Environmental Protection Agency. Where an analysis indicates that the source initially would not meet such standards, the applicant shall provide a proposed method of water treatment, or condition of, such as chlorinating, filtration, or chemical adjustment to meet such standards.

Test Method
Pumped Source

Address of Well                                                                                                                 

Date Well Was Developed                                   Date of Pump Test                                    

Minimum Sustained Yield From Rules & Regulations                   Gal/Min                 Gal/3-day

	Time Distance from Ground Surface To Water Pumping Rate Total Volume Drawn From Well Step 1                AM/PM                      FT (Below Surface)     Step 2                        GAM                     GAL Step 3                AM/PM (Pumped dry)                      GAM   Step 4              AM/PM              AM/PM              AM/PM              AM/PM(continue on an additional sheet if necessary)                     GAM                   GAM                   GAM                   GAM                       GAL                     GAL                     GAL Step 5              AM/PM                       FT     Step 6   72 FRS     After Step 5                       FT

For the well be acceptable, the final pumping rate AND the total volume of water drawn from the well must exceed the minimum sustained yields AND a 100% recovery in the water level must be realized.

	Name of Company:                                                                                                               C-57 License #:                                               Signature of tester

	Test Method Gravity Source

	Test #1 Test #2 Test #3 DATE:       1.                Gal/               Min                   Gal/               Min           Gal/               Min 2.                Gal/               Min                Gal/               Min           Gal/              Min 3.                Gal/               Min                Gal/               Min           Gal/              Min   Test #1 Average Test #2 Average Test #3 Average                  Gal/               Min                Gal/              Min           Gal/            Min

	Yield = Lowest Average =                       GAM                                                                                                                                                                                                                                     Signature of Tester                                                                                      Firm:                                                                                                                                    Phone:                                            Instructions on how to perform the gravity source testing can be bound in the Marin County Rules and Regulations for Domestic Water Supplies.