Patching a leaky cistern (pools, tank, laundry room, concrete)

[jtab4994]

We get our water from a spring, up the mountain from our house. The water is captured in a cinderblock cistern, covered by a spring house, and pumped into a pressure tank in the laundry room.

Lately I've noticed the water level has dropped and does not go above a certain level, which tells me there is a leak/crack at that level.

I am inclined to patch it with Hydraulic Patch from by Quickrete or DryLock. After the patching is done successfully, the patched area will almost always be underwater. Is that the best stuff to use? Are there better options for underwater use?

[K'ledgeBldr]

Replace the block with a plastic cistern. It will last decades beyond the concrete block. Just insist on one made of virgin HDPE.

[jtab4994]

Originally Posted by K'ledgeBldr

Replace the block with a plastic cistern. It will last decades beyond the concrete block. Just insist on one made of virgin HDPE.

Wow, never thought of that! Are they custom made, like Bath Fitter? How do I find a guy to do that?

Edit: Thinking it through -- I suppose I could get a new HDPE tank and have it buried, closer to the house and along the water line. Would be difficult to go up the mountain to bury a new tank and relink the lines. There is a buried "junction box" with a shutoff valve that would be an ideal spot. So the cinderblock spring house can stay put, and feed the HDPE cistern.

[harry chickpea]

With a spring and cistern, you want to be concerned about daily use and also about the ability to have enough water to extinguish a fire that doesn't require the fire department. Adding an additional cistern is a good way to do that.

In answer to your original question, those products would work fine. Inground swimming pools are often finished with a lime based sealant that works well and I would consider "safe" but YMMV.

A new (obviously) septic tank is also something that can be pressed into use as a cistern.

[jtab4994]

Originally Posted by harry chickpea

...

In answer to your original question, those products would work fine. Inground swimming pools are often finished with a lime based sealant that works well and I would consider "safe" but YMMV.

...

Thanks, I see a product online called Perma Pool Patch that is made to be submerged. Adding an HDPE cistern is a longer term project.

[Threerun]

We have a formed concrete cistern fed from a well and whenever we have questions we call this company called Western Water Works and they tell me how to handle it. I’m sure a company the specializes in these sorts of things will tell you their experience with the best products to use especially in your area.