Question:I believe drainfields start ponding when the user of the onsite system adds too much water to the drainfield. With a well-maintained septic tank biomat, I believe hydraulic conductivity tends to stabilize at approximately 0.20 gpd/sf, based on a scientific analysis of the flow into a soil. If the owner has 100 square feet of trench bottom, they can drain 0.20 x 100 = 20 gpd. Most homes would need 500 square feet of trench bottom to avoid ponding. What are your comments about ponding and drainfield sizing?Answer:I agree ponding will take place in the bottom of the soil treatment
