26.04.04.26

.26 Minimum Yield and Yield Testing for Domestic Water Supply Wells.

A. A domestic well or double well combination shall produce a minimum yield of 1 gallon per minute for 6 hours.

B. Replacement wells servicing an existing dwelling are exempt from the minimum yield requirement of 1 gallon per minute.

C. The Approving Authority may require a mandatory yield test in any hydrogeologic area of the State for any well, if it is determined that a yield test is necessary to assure an adequate water supply.

D. The County Water and Sewer Plan shall delineate those areas where a mandatory yield test is required for water supply wells in Hydrogeologic Areas 1, 2, 4, and 5.

E. Each domestic well in Hydrogeologic Area 3 shall be tested for yield in accordance with §G of this regulation unless the requirement has been waived pursuant to §F of this regulation.

F. The County Water and Sewer Plan shall delineate those areas in Hydrogeologic Area 3 where the mandatory yield test is waived.

G. Yield Test Procedures.

(1) Except as provided in §F of this regulation, all domestic wells drilled in Hydrogeologic Area 3 shall be yield tested as provided below:

(a) On the yield test report form, the permittee shall note pertinent data related to the yield test, including but not limited to:

(i) Static water level;

(ii) Measured depth of well;

(iii) Whether the well has been hydrofractured;

(iv) Estimated well yield prior to hydrofracturing;

(v) Depth of test pump in well;

(vi) Name of the person performing the test;

(vii) License number of person performing test; and

(viii) Well construction permit number;

(b) The pump and related equipment shall be placed in the well;

(c) Pumping shall begin at a rate of withdrawal greater than 8 gallons per minute until the water level drops to a point close to the pump;

(d) If the water level drops to near the pump, the pumping rate shall be adjusted so that the water level remains constant;

(e) Measure and record the flow rate of water discharged and water level at 15 minute intervals throughout the test; and

(f) Discharge water at least 50 feet from the well and any on-site sewage disposal system.

(2) A single interruption of pumping of up to 15 minutes due to equipment failure or other unusual circumstances is permitted, but the amount of down time shall be made up by additional pumping at the end of the test.

(3) The criteria for approval shall be a minimum yield of one gallon per minute for 6 hours continuous pumpring after the well has been pumped out as provided in §G(1)(c) of this regulation.

(4) The pump test may be terminated early and the well yield shall be considered adequate if a well:

(a) Cannot be pumped out after 3 hours pumping as provided in §G(1)(c) of this regulation; or

(b) Yields 4 gallons per minute or greater for 3 hours continuous pumping, after the well has been pumped out as provided in §G(1)(c) of this regulation.

H. The Approving Authority may permit two wells to be connected to meet the minimum yield requirement if:

(1) A written request is submitted to the Approving Authority for each installation;

(2) The wells to be connected are tested in accordance with the yield test procedures of this chapter;

(3) Each well demonstrates a yield of at least 0.5 gallons per minute during the yield test; and

(4) Both wells are tested for yield at the same time.

I. The yield test data shall be submitted to the Approving Authority for review.

J. Domestic Water Supply System Standard.

(1) The water supply system shall produce not less than 500 gallons of water in a 2-hour period, at least once each day.

(2) If the sustained yield of the well is not capable of meeting the total water supply standard, sufficient storage shall be provided.

K. Well Storage.

(1) If well storage is selected, the amount of storage required is calculated by subtracting the well's yield over a 2-hour period from 500 gallons.

(2) A quantity of water in storage is equal to the number of feet below the static water level and 10 feet from the bottom of the well, multiplied times 1.5 gallons per foot for a 6-inch well or 0.65 gallons per foot for a 4-inch well.