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Abandoned Well Sealing cost


Huskie

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I might have an old well on a rental property that I own and am thinking of selling. The city now requires that the owner seals up the well before the property can be sold. Anyone care to venture a guess as to the total cost of this unexpected project in extreme southern Mn?

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I don't understand the reasoning behind sealing a well. Why not just dig down, cut the pipe off, and back fill?

The reason I always get is, "To prevent contamination." Contamination from what? Rain water draining down to the water table? That's a bunch of hooey. If the casing is filled with dirt what contamination can enter via the old casing that can't enter through the ground around the outside of the casing? I'll answer that. None!

Sounds to me like just another one of our many feel good solutions.

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I believe water filters through more than just "dirt" before it gets to your ground water.

Everyone has an opinion on how to do something and I am not saying your right or wrong, but messing with your drinking water wouldn't one want to make sue it was done correctly?

Just asking!

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Real world experience having been a mayor some years back that had to have a few done plus I bought a building a year ago from the city that had to have a well sealed and the latest bill was 1900 dollars. I believe the ones that we did a few years ago were closer to a thousand dollars. My guess is the price is dictated by how deep and how wide they have to fill.

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Typically the aquifer the well goes into is isolated from the surface by some sort of impervious layer of rock or clay. The well pierces that layer. The surface water will carry impurities and nitrates into the aquifer. Filling the well with grout will prevent that.

I don't think you want the runoff from the pasture full of cow excrement or the runoff from the street with oil, gas, salt, and doggy do to go into the nice pure water that has been filtered through 100 miles of st peter or jordan sandstone.

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My point is this. When a well is drilled the hole is larger than the casing. Any water that might perculate through soil inside the old well casing can just as easily follow along the ouside of the well casing. In fact, most of the water that would find its way down to the bottom because of the well, would do so along the outside of the casing. If you fill the casing with soil the result is no different than what is found around the outside of the casing.

We drilled a new well this past year. The first attempt went down 90+ feet and the well head broke forcing the driller to stop. Because it was January 2012 he didn't want to leave his drill rig set up and potentially freeze so he took it all down and left until he could get the parts fixed.

It's not possible to get set up in exactly the same place to continue drilling so a few months later after spring thaw when he came back he had to start all over. He moved over about 10 or 15 feet and drilled again. He got down to 145 feet and hit bedrock on a dry well. So, we were forced to move and try a third time. Third time was the charm and so we were finally done.

If the drilled hole is the problem because it somehow provides a path to the depths then why was it not required for him to seal those two dry holes? We didn't have to move very far to find our new water supply. Anything that might drain down through those two small diameter holes can find its way to our water supply.

I'm not buying it.

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Typically the aquifer the well goes into is isolated from the surface by some sort of impervious layer of rock or clay. The well pierces that layer. The surface water will carry impurities and nitrates into the aquifer. Filling the well with grout will prevent that.

I don't think you want the runoff from the pasture full of cow excrement or the runoff from the street with oil, gas, salt, and doggy do to go into the nice pure water that has been filtered through 100 miles of st peter or jordan sandstone.

How do you suppose that aquafer gets replenished? Water must be working its way down there somehow. If not through the soil from the surface then how?

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It gets replenished a long way from the well. As for the casing, aren't most wells grouted around the casing?

Well owner's handbook

Quote:
The rotary drilling method produces a bore hole which is larger in diameter than the casing. The space between the outside of the well casing and the bore hole wall is called the annular space. After the well casing has been placed in the bore hole, it is necessary to fill the annular space to keep surface water and other contaminants from entering the well. The material used to fill this annular space is called

grout, a specific mixture of water and cement, or water

and “bentonite” clay, and sometimes other permitted additives such as sand.

According to Minnesota law, the grout must be pumped in from the bottom of

the well upward, to assure a complete seal around the casing. The usual

method is to insert a ¾ to 1¼ inch diameter pipe (known as a grout pipe or

tremie pipe ) down to the bottom of the space between the well casing and the bore hole. The grout is then pumped in until it comes to the ground surface. The grout must not be poured from the surface.

All rotary-drilled wells must be grouted from a required minimum depth to the surface or to the base of the pitless adapter or unit, which is illustrated in Figure 3. There are additional grouting requirements for some other types of wells, such as flowing wells, and wells drilled in certain kinds of rock.

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bobt...the well contractor is required by the well code to seal those dry holes. he is even required to record that information along with the new well record with the MN Dept of Health. Its possible the contractor did seal the borings and you just didnt notice. they weill often times grout the hole with the same tooling in the hole. when they pull off they are allowed to fill top 10 feet with cuttings. If it was my property I would want those dry holes sealed. They not only provide a point source for contamination but are also dangerous if someone should step in one. check it out. call the governing MDH office in the region. There should be a well record and 2 reports with H numbers also on file. if they didnt do it it could really open a can of worms for the contractor but if he did it right then no problems. my .02

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I see. So the well is grouted above the screen to the surface on the outside of the casing. Therefore, if the inside of an old casing is also grouted then I can see where the seal is solid. Makes more sense now.

As far as sealing the dry holes, I guess it is possible he did it when I was not around. I was not there all the while he was doing his work.

Thanks for the education.

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