Sand in my Sandpoint Well water

[ApoJake]

Hi!

I purchased a house that has a sandpoint well installed in ~1990. This is a direct driven point well (no casing) that is a 2" steel pipe that is only used for an underground irrigation system. When I did the washer-on-a-string method, I measured a depth of 23 feet until I hit the bottom so I'm assuming it's a 3' sandpoint with 20' of riser pipe.

The previous owner told me he would put a gallon of muriatic acid down there once every year or every other year to keep the screen clean. After a couple of years of not doing it after I purchased the house, I decided to give it a shot.

I put a gallon of 30% muriatic acid down the well and now I get a lot of sand that comes up. There is no issue with the water flow - there's plenty of water. It just now has a LOT of sand in it. The flow previously was pretty good still as it was able to run 3 gear-driven sprinkler heads without any problems and no sand. But now, basically when I turn the pump on, I get an initial burst of very sandy water and then after some time, it will become less sandy (in a matter of maybe 5 minutes or so). I've let the pump run for over 1 1/2 hours and it would still have some sand in the water. If I turn the pump off and repeat this step, I get the same result. Very sandy initial flow, but less sandy over time. I've repeated this several times and it seems to be the same every time.

So my question is this: Could the acid have eaten a hole through the screen on the point? Or could it perhaps be that I just loosened up a bunch of sediment that was caked on the well screen and I just need to keep trying to flush the system. I would have thought that after trying it several times it would have improved but it doesn't seem to be doing so.

This all happened in July of last year (2017) so after messing with it for the whole rest of the summer and not getting any positive results, I abandoned the project. Now that it is spring I'm basically at a decision point of whether I need to keep trying to salvage the well I have (if possible) or just drive a new point next to it. I'm not sure what the lifespan is on a sandpoint well but if it's already almost 30 years old, I'm wondering if it may be more beneficial to just drive a new point...

Thanks in advance for any advice!

Jake

 

[Valveman]

The screen on the sandpoint should be small enough to keep the sand out. My guess is the acid ate a hole in the screen. Probably best to just drive in a new point.

 

[Sponsor]

 

[LLigetfa]

The flow previously was pretty good still as it was able to run 3 gear-driven sprinkler heads without any problems and no sand.

You overlooked the "if it aint broke, don't fix it" rule. At least with only 20 feet of pipe, it should not be too hard to pull up the old sand point and replace it.

 

[ApoJake]

Yeah lesson learned I suppose.

I think my plan is to just cap and abandon the existing well (as I don't really have an effective way to pull it) and drive the new one with a jack hammer about a foot or so next to it. Then just re-route the piping to the pump.

Right now, the well comes up and does a 90 degree turn from vertical to horizontal to the pump. My plan is to have the new well come up, do a 90 to go horizontal, and then I'd have to do a 45 degree turn to the left or right (when looking down on it) to get back to the pump. Would that extra 45 degree turn affect the flow in any way? I can't imagine it would, but I am by no means a plumber that understands flow rates in pipes.

Once I drive the new point down to the depth I need to go, should I expect there to be some muddy water at first that would need to be flushed out? And if so, how long should it take for that water to become sand/mud-free to be able to be used for my irrigation system?

Thanks again in advance for your guys' expertise!