cleaning out fresh water tank?

[chetking@gmail.com]

I would dispute the “fact” that water wells provide a way for surface contamination to reach the water table. As a retired water well driller I know that is not true. In Washington state and most other states too it is a requirement that all wells are sealed down to at least 20’. For instance in a 6” diameter well we are required to drill a two inch oversized hole the first 18’. So we drill a 10” diameter surface hole and fill the void (2” all the way around the 6” casing) with a bentonite solution or powdered or granulated. Bentonite swells to about ten times it’s original size when dampened. This gives a very secure seal that does not allow any contamination to enter the water table.
That’s from my years of drilling.

[lwmcguire]

Old water wells were gravel packed and the dirt

Most states did start legislation to require retards some years back

Even now properly constructed wells often are in flood zones

Unfortunately significant contamination does enter the aquifer via wells

In the farm country wells were drilled or dug at every homestead and not properly abandoned

Now current laws do require proper retards in most cases

Back flow prevention is also required but does fail

Never ever assume that your water source is pristine unless it is tested and monitored

[Roark]

Originally Posted by lwmcguire

Old water wells were gravel packed and the dirt

Most states did start legislation to require retards some years back

Even now properly constructed wells often are in flood zones

Unfortunately significant contamination does enter the aquifer via wells

In the farm country wells were drilled or dug at every homestead and not properly abandoned

Now current laws do require proper retards in most cases

Back flow prevention is also required but does fail

Never ever assume that your water source is pristine unless it is tested and monitored

What he said. Flooded wells, old hand dug, driven, and improperly abandoned wells, in addition to the hundreds of large commercial and industrial agricultural wells that are sunk without permit.