WorldWide Drilling Resource

11 AUGUST 2022 WorldWide Drilling Resource® Environmental Monitoring by Thomas Kwader, Ph.D., P.G. Owner, Qwater Well Developer and WorldWide Drilling Resource® Hydrogeologist Protect the Well by Taking Care of the Septic Tank ~ Part 1 Many rural homes have a small domestic well, an underground septic tank, and drain field. Ideally, both the well and tank can operate for years without failing to do what they were designed for - which is to pump and dispose of clean wastewater back into the shallow aquifer. Many homeowners may not even know where these features are located on their property or how wide and deep they extend underground. A septic tank should be located downhill or down radient of the well at a distance of at least 30 feet away. If the well is withdrawing water from a shallow water table at a relatively shallow depth, the separation distance should be maximized to prevent the well from pulling water from the area around the septic tank and leach field. The “cone of influence” of the pumping well should always be upgradient of the water level in the septic tank leach field. This can be checked by installing smalldiameter piezometers into the water table of the well and at the leach field. If the well is also used for irrigation, or the septic tank receives more water than the domestic well pumps, this could cause a reversal of the groundwater gradient causing the septic tank to flow toward the cone of depression of the portable well. Periodically checking the water well for the presence of coliform bacteria will help confirm the well water is not flowing uphill and is suitable for drinking purposes. It should be noted, the house well and the septic tank/drain field are not always installed by the same contractor or constructed at the same time; however, each contractor has an obligation to be aware of where the other system is located and are kept a safe distance from each other for the systems to operate properly and safely for many years into the future. If the septic tank installer or well drilling contractor are not governed by municipal government rules (setback distances), it would be advisable to consult with a soil scientist or engineer to determine the minimum safe distance for the specific site. Tom Tom Kwader may be contacted via e-mail to ENV