High chloride in well water

[frankly]

We just dug a well prior to construction of a new home. the chloride tested high at 385. How bad is this really? Is there any easy way to treat it? the well was dug to 225'. It has been suggested that another well with casing dug to a deeper level would probably find an aquifer of better quality. Is this likley? Any thoughts or comments would be much apprciated.

 

[TJWATKINSPG]

frankly,
There is a little more information needed to answer this question. The cloride content of your water is going to be determined by the source of the water. This has a great deal to do with the type of rock or soil that it is in. Casing off an upper aquifer could reduce your chloride content if you live in an area that is near te ocean for example. It may not help at all in other cases. First where is the well drilled? Second how deep is the original casing set?( What is your screened interval?)

The truth will set you free. Best of luck. Geodude

 

[frankly]

Geodude
Thanks for your reply. The well is in Massachusetts about 30 miles from the ocean. It is on a hill about 470 ft above sea level. There are no highways within miles and even the state road, Route 20, is a couple of miles away so road salt seems unlikely. The well was actually dug a few years ago by the owner of the land. We just retested it now. The well digger can't seem to come up with the drilling report so I don't know how much casing was used. My guess would be minimal.

 

[falcon4]

There is a mariad of things to consider here.
I would start with a fresh water sample and ask your local health department what is an acceptable level of chloride for humans.

Is it chloride from dissolved salt or residual chlorine from disinfecting the well?

There are many cases where the well was treated with "clorox" to kill any induced bacteria. This needs to be removed, by pumping the well to remove traces of the chlorine still in the water sample.

If it is chlorides from dissolved salts a little investigation needs to be done. Ask the original "driller" if Salty water is possible in that area and depth. Drillers typically know aquifers and their conditions in different areas. If the driller has no information I'd contact your local Department of Environmental conservation or Geology and ask them if there is sedimentary rock layers in your area. Typically salty aquifers can be the result of disolving bedrock salts into the ground water.

If the last turns out to be your condition then it gets expensive. Water treatment is costly but possible. Re-drilling the well means knowing exactly where the problem water is coming from (which you're not sure).

Casing the well deeper may not be the answer if all deeper aquifers are equally or worse in chloride levels.

Hopefully pumping the well a while will result in a fresh sample that tests acceptably

 

[Eduardo5000]

I would advice you to check the regional and local geology, in order to determine the recharge zone. If you or your driller know the aquifer characteristics, and they don't match with the analysis of the water you tested, check for rests from the wheel development process.

 

[TJWATKINSPG]

FRANKLY
I would agree with EDUARDO at this point. Where you are in Mass is underlain with meta-sedimentary rocks that can vary widely in very short distances. Often you need to seek local advice. Sometimes the only local advice is experinced yet un-trained. It does seem reasonable that by tapping into a different aquifer that the water chemistry would change. Thus drilling deeper may repeat May achieve your goal. The hint from falcon4 that the chlorides could be introduced post drilling is a good thought. If you don't want to spend huge amounts on lab testing look into pool test kits, test your water then produce a significant amount.(try 3 well volumes) Test again, if there is a change it might give a hint as to the souce of your chloride ions.

The truth will set you free. Best of luck. Geodude