Suddenly... SAND! (after months' ago upgrading pump to higher HP?)

Over the last month, I've been dealing with my whole house water filter (after the pressure tank) clogging with sand every few days. Toilet tanks and bowls will accumulate a 1/2" base of sand, if the family don't think it important to change the filter until I get home and notice it... :^( First clue is a decrease in water pressure.

The house is located on what I've been told is "glacial till" (a tree-covered sand dune containing assorted boulders left by a retreating glacier), but there's plenty of sand.

Last fall I replaced a failed 1/2hp pump with a 3/4. Pump is placed at same height in well. The well particulars are: 99' deep, pump at 94', top of water at 59', 6" casing to 54'. No indication of bedrock. The well is about 6' from the edge of the basement. Family of 5, youngest already a teen. Well itself is 40 years old this year, same age as house.

The newby in me wants to raise the pump 5', to buy time, because I sense the well is failing.

Q1. Is it failing? How? Casing? (We had an unusually long period of deep freeze this winter, and ground frost went extra deep.)
Q2. Is it reasonable to presume it's cased to bedrock? If so, is there a seal there which could have failed?
Q3. Is it reasonable to conclude the upgrade to a higher hp pump is not the cause, because of the many months that have elapsed since the appearance of the symptom?
Q4. Is there any hope of rehabilitating the well? Perhaps by extending the casing, or inserting smaller inside larger?
Q5. Is the appearance of sand at the surface, equivalent to the increase of a hole in the well, creating a risk of subsidence?
Q6. Would there be any benefit, permanent or temporary, to raising the pump 5'? 10'? I'm thinking if the sand "catches up to it" again, at its higher level, that's an even surer sign of a collapsing well, if there is such a term.
Q7. Regarding a new well, how far from the old well would be prudent? If I go to the other side of the house, all my well plumbing is on the wrong side... :^(
Q8. Anything else to try to help with a diagnosis or remediation?

I apologize for the flood of questions: I've got a little shell-shock going on.

But I am grateful this forum is here. Thanks.

Do you know if it is even a rock bore? It could be you have a mud well and the formation has become unstable. If you raise the pump you will most likely just raise the sand level in the casing, assuming it is in casing.

I think it's time to talk to well driller and maybe put a camera down the hole. If it is a mud well, you might be able to blow out the casing by air raising, and then put down a smaller diameter screened casing. It is also possible the driller may be able to setup atop the existing well and drill down through the casing down into rock.

My well is a mud well. Twice I've had to clean the sand/clay out of it. The first time the driller came back and dropped a few thousand gallons into the well. It likely pushed some of the sand back into the cavity but most of it washed out the top. Then he dumped some crushed stone in to supposedly hold back the sand. The second time I could not convince him to come out and do it again so I manually bailed out as much of the clay/sand as I could and then used my old pump to suck out as much as it could before it wore out.

The driller offered to drill down through the existing casing down into rock. Around here, the rock is the Canadian Shield which is mostly solid granite with very few water veins. One can go down hundreds of feet at $48 per foot before finding water. I don't $15,000 to sink into the well so I live with it.

What I found with my well is that if I limit the GPM that it will not motivate the sand/clay. I have a micronizer for iron that acts as a dole valve. This Winter, I made the mistake of opening the bypass on it a little too much to increase the GPM and it stirred up the well. This Summer I will have to pull the pump and bail it yet again. My old pump is too worn to be of much use this time and I hate to wear out my new pump, so will need to consider air lifting if it is not too expensive to rent the compressor.

My casing stops about a foot before the bedrock so putting down a screened casing is not an option.

LLigetfa said:

Do you know if it is even a rock bore? It could be you have a mud well and the formation has become unstable.

Click to expand...

I sure don't. Given what I was told about the glacier ("the sand can be a 100' thick!"), a mud well (which I take to mean a well whose sides are held up by a drilling mud coating) would make sense. I do know my casing is 54' out of 99', but I don't know why...

I think it's time to talk to well driller and maybe put a camera down the hole. If it is a mud well, you might be able to blow out the casing by air raising, and then put down a smaller diameter screened casing. It is also possible the driller may be able to setup atop the existing well and drill down through the casing down into rock.

Click to expand...

Exactly what I wanted to know LL [forgive me I cannot pronounce your name because I am not Canadian] before I approached a driller. I did in fact approach one shortly after we moved in about videoing my well, and the response I got was: "Are you sure? Or for the same price, don't you just want a new well?"

My well is a mud well. Twice I've had to clean the sand/clay out of it. The first time the driller came back and dropped a few thousand gallons into the well. It likely pushed some of the sand back into the cavity but most of it washed out the top. Then he dumped some crushed stone in to supposedly hold back the sand. The second time I could not convince him to come out and do it again so I manually bailed out as much of the clay/sand as I could and then used my old pump to suck out as much as it could before it wore out.

Click to expand...

Telling myself, I could be on top of solid granite, for heaven's sake.

What I found with my well is that if I limit the GPM that it will not motivate the sand/clay. I have a micronizer for iron that acts as a dole valve. This Winter, I made the mistake of opening the bypass on it a little too much to increase the GPM and it stirred up the well. This Summer I will have to pull the pump and bail it yet again.

Click to expand...

They don't tell you when you buy a house that you don't "own" the well, you have a "relationship" with it... I had heard of the [Dole] flow restrictor, but I thought my 3/4 pump at 10gpm was no different than my 1/2hp at 10gpm. With the pressure tank, I don't suppose I care if I go down to 5gpm.

But should I get that 3/4 out of the well and go back to a 1/2hp?

Thanks, LLigetfa. I don't feel so lost.

GottaTry said:

I sure don't. Given what I was told about the glacier ("the sand can be a 100' thick!"), a mud well (which I take to mean a well whose sides are held up by a drilling mud coating) would make sense. I do know my casing is 54' out of 99', but I don't know why...




Exactly what I wanted to know LL [forgive me I cannot pronounce your name because I am not Canadian] before I approached a driller. I did in fact approach one shortly after we moved in about videoing my well, and the response I got was: "Are you sure? Or for the same price, don't you just want a new well?"



Telling myself, I could be on top of solid granite, for heaven's sake.



They don't tell you when you buy a house that you don't "own" the well, you have a "relationship" with it... I had heard of the [Dole] flow restrictor, but I thought my 3/4 pump at 10gpm was no different than my 1/2hp at 10gpm. With the pressure tank, I don't suppose I care if I go down to 5gpm.

But should I get that 3/4 out of the well and go back to a 1/2hp?

Thanks, LLigetfa. I don't feel so lost.

Click to expand...

There are lots of reasons that this well could fail, and lots of possibilities to fix it, and possibly nothing you can do to fix it. I doubt raising the pump or restricting the flow will give you any long term benefit or solution. To know what the problem is and attempt to fix it, as mentioned before a video is absolutely necessary.....soooooo If the well driller says you can drill a new well for the cost of a video, I'd really look into that. A 100' well shouldn't cost more than about 2000-3000 (around here anyway), and you'd easily be at that number for a video, labor, and repair job that may not either be possible or completely remedy the problem.

Just an observer here... Just a comment or two.. there are filters that don't need replaceable elements. People speak well of this filter: http://www.twistiiclean.com/ Maybe you need something more , but read up on it. It may improve things for you.

Raising your pump makes sense to me. Also, there is a process where they blow a geyser of sand out of your well with a big air compressor by sending air down a pipe.

Replaceable filter elements or not, that much sand will quickly destroy a pump, fill the water lines with sand, and could even collapse the well. There is always a reason for the sand. My guess is a hole in your drop pipe that is stirring up the well. If you can pull it yourself, you might want to check it out before going to extremes.

GottaTry said:

I thought my 3/4 pump at 10gpm was no different than my 1/2hp at 10gpm...

Click to expand...

They most likely have different curves and the extra HP may put it higher on the curve resulting in more GPM. If the pump cycles a lot and the well recovery rate is low, the cycling may perform a surge action that can motivate the sand. The solution to the frequent cycling is to try to match the draw to the usage, not a bigger tank. A bigger tank may draw down a slow recovering well more and worsen the problem.

It would be good to know what the recovery rate is and if the well is even worth the effort to remediate. It would also be good to know how fine or coarse this sand is to know if a slotted casing might hold it back.

In the end, you are dealing with a 40 year old well and who knows what shape the casing is in. Some old wells open up over time, others stop up over time.