Cleaning a water well

[Cord]

I've been battling a well for a couple of years now and really thought I had the upper hand. Apparently not. When we first purchased the property it had been vacant for a while and the stagnant water was coal black and had a stringy slime in it. I'm told that this is iron bacteria and although unsightly it's harmless. We've installed a iron filter and with use the water has cleaned up. We recently replaced the well pump and went with a larger unit and this seems to have upset the apple cart. While the pump was hanging from the rig we flushed the well and got the same black water. This doesn't surprise me because the unrestricted pump was sucking pretty hard. The water really wasn't cleaning up so I asked the pump guy to leave the pipe hanging off the well casing and I'd run it later. Later in the day I ran the water for several hours and saw the color shift from black to gray to clear. Thought I was done so we dropped it back into the pitless. The next day we filled some 330 gallon totes and got more gray water. I also was battling a clogging issue with my screen filter because it was clogging. Desperate for a large volume of water, I removed the filter and installed a valve so I could isolate the domestic water system. Several times I saw clear water alternated with the gray water. Later in the day the color started to shift to brown. Now that we've pumped several thousand gallons of water there is a thick layer of fine mud in the bottom of the totes. Done for the day, I watered some plants and then checked the water quality off the sampling faucet. It was clear but did have a dark tint to the water. Thinking I was OK I reinstalled the screen filter and took a shower. Before I could finish my shower I saw brown water. Another slug of mud must have been sucked up and made it past the filter, iron filter and softener. Checked the water again this morning and it was clear so I set the iron filter to regen before I left for work. If it's still clear, I'll regenerate and then flush the softener system out tonight.

We just planted a new lawn and it appears we are headed toward a dry summer. This means I'll be sucking on this well pretty hard to run the sprinklers. I can't be coming home to find the domestic system was contaminated once again by this fine silt. I talked to the well guy this morning and he was less enthused with helping me. Guess that's what I get for supplying my own pump for him to install. I was wondering if any members have experience with a problem like this? I'm thinking I need to somehow clean out the well and remove the silt. I was thinking of pulling the pump up and resting the pitless on the casing and then using compressed air to help break the material up so it could be pumped out. Thoughts?????

365' well drilled in the 60's. The well is fully cased into a gravel bed so it only draws from the bottom of the casing. The well report (attached) doesn't mention the use of a screen. The pump is down 200' from the pitless and it's a 22 gpm pump. The well guy estimated the free flow at over 30 gpm and we ran it like this for several hours. This is obviously a very good well and I think it's worth the effort to try and save it.

 

[groundcover]

I would start with a chlorine shock. Dump a couple of gallons of bleach down the well, run a hose till you smell it, run the hose into the well to mix it up , then run the hose to waste till things clear up.

 

[CobyRupert]

Did you run it for several hours/ 1000's gallons continuously?
Seems like your keeping the silt stirred up, having it flow in and directly pumping it out vs taking water that has had a chance to precipitate the silt to the bottom. Instead the silt falls out to the bottom of your totes.

2 cents.

 

[RedNeckRacin]

This may be a dumb question, Are there any centralizers and an anti-torque collar on the tubing string?

 

[Cord]

The old pump had a iron drop pipe without a anti torque collar. One was added for the new pump because we went with a pvc drop pipe. Don't know what a centralizer it, but we don't have it anyways.

No, it was not continuous. We would pump 700 gallons and then stop because we'd have two totes full. I think the water may have cleared up when we were pumping continuously because it wasn't getting stirred up.

From what I've read, the problem is "percipates from iron". In other words, the iron is dissolved in the water and when it enters the oxygenated well shaft it solidifies and falls to the bottom of the hole. I believe that I'm now disturbing this material and it's making it up to the pump. To that effect I was thinking I need to stir things up more so I can reach them with the pump.

 

[bspeedy]

First of all, congratulations on having an abundant water supply. Many folks on this board are not so lucky.
From the well log, it looks like it was drilled in 1958. 10 inch casing set to a depth of 20 feet - likely that was the minimum requirement at that time. Also 6 inch casing set down inside to full depth. The inside (6")casing would have been perforated near the bottom - perhaps the last 2 or 3 joints - to allow water in and keep out sand and gravel. I suspect that your source of contamination is water that was cased off originally. Typically, water flows into a well from various depths. Upper water may have iron or other bad attributes, thus it would be cased off during drilling. With the setup of your well and the age of the casing, it is very likely that the upper (bad) water is finding it's way in through holes in the casing that have rusted through over time. It's very difficult to determine this for sure because, due to the high rate of water production, your well cannot be pumped dry with your current pump.
I would consult with a local drilling contractor. He may be able to advise you on saving this well. I would try to find someone who would clean out the well to it's original depth and set plastic casing down inside the 6" steel casing. This new casing could then be grouted to allow the upper water to be sealed off.
The reason you see water go from good to bad to good is very typical of a well with the issues I've described.
If possible, try to find the son - or grandson - of the original driller. He will have two things going for him - he will have years of experience in your area and he will be interested and excited to work on a well that his ancestor installed. FYI - my brother is running the family drilling business which was started by my grandfather. No one in the area has a better understanding of the local geology and what to expect underground.

 

[bspeedy]

By the way, one more thought...
I don't recommend spending more money on filtration equipment until you get to the root of the problem. The filters I've seen, which can cost into the thousands of dollars, don't do a lot except waste money and electricity.

 

[Ed of all trades]

I would dump 2 gallons of bleach in as was said above wait until you can't smell the bleach in the water and do it again. I have done that with well that had flood water in them and they tested good. It might not help but it can't hurt and ti is a cheep fix if it does work.

 

[Cord]

By the way, one more thought...
I don't recommend spending more money on filtration equipment until you get to the root of the problem. The filters I've seen, which can cost into the thousands of dollars, don't do a lot except waste money and electricity.

I agree with you on the second point. It would seem to me that buying additional filters is just a band-aid for the problem.

The installer estimated the new pump was free flowing over the casing at 30gpm plus. This would be feasible because it wasn't building much pressure. I know that at 70 psi the pump will still flow 17 gpm which I knew the well would deliver per the report. Even at 30 gpm over several hours I was not able to draw the water level down to the pump. Now, I'm wishing I had gone with a bigger pump!

 

[Cord]

I would dump 2 gallons of bleach in as was said above wait until you can't smell the bleach in the water and do it again. I have done that with well that had flood water in them and they tested good. It might not help but it can't hurt and ti is a cheep fix if it does work.

As a requirement; when the pump was replaced the well was chlorinated. This is the reason why I waited several hours before pumping over the casing.