Subject to Env-Wq 1007.06, the individual conducting the percolation test shall:

1. (a) Remove any smeared soil surfaces and provide a natural soil interface into which water will percolate;
2. (b) Remove all loose material from the hole;
3. (c) Add 2 inches of coarse sand or fine gravel to protect the bottom of the hole from scouring and sediment;
4. (d) Fill the hole with clear water to a minimum depth of 12 inches over the gravel and maintain water in the hole for at least 2 hours, or until the drop in water as measured in accordance with (e), below, reaches steady state;
5. (e) Determine the rate of water loss 2 hours after water is first added to the hole to insure that the soil is given ample opportunity to swell and to approach the condition it will be in during the wettest season of the year;
6. (f) Add clear water to bring the depth of water in the hole to approximately 6 inches over the gravel, after the rate of water loss has stabilized;
7. (g) Measure the drop in water level from a fixed reference point, at approximately 10 minute intervals for one hour, refilling 6 inches over the gravel as necessary; and
8. (h) Use the drop that occurs during the final 30-minute period to calculate the percolation rate.

Source. (See Revision Notes #1 and #2 at chapter heading for Env-Wq 1000) #11184, eff 10-1-16; ss by #14486, eff 2-1-26, EXPIRES: 2-1-36