How common are leaks in Gunite pools?

[shoot_the_goalie]

My pool is fine, but just curious for the furthering of my pool education.

How common are leaks in gunite/concrete pools? I know it's common to possibly have small leaks at the skimmer joints, plumbing, etc, but how common is it to have a leak in the actual re-barred vessel? Also, in general are most pool leaks small and gradual leaks? What's the likelihood that a gunite/concrete pool could suffer a catastrophic leak outside of a major act of god event (earthquake, mudslide, etc). Also, outside of leaks, what's the average life span for a gunite/concrete pool vessel if properly maintained (I know plaster needs to be resurfaced periodically)

Thanks

 

[ajw22]

My pool is fine, but just curious for the furthering of my pool education.

How common are leaks in gunite/concrete pools?

The leaks seem to be in the interfaces - light niches, skimmers, tile lines - or plumbing and not the pool shell.

I know it's common to possibly have small leaks at the skimmer joints, plumbing, etc, but how common is it to have a leak in the actual re-barred vessel?

Not very common. Takes a lot to have a crack through the plaster and gunite to where you lose significant water. One person here this year had a bunch of cracks in their pool due to soil erosion and settling of the entire pool. But he was not losing water.

Also, in general are most pool leaks small and gradual leaks?

I have not heard of anyone losing thousands of gallons of water from their pool overnight, if that is what you are asking.

What's the likelihood that a gunite/concrete pool could suffer a catastrophic leak outside of a major act of god event (earthquake, mudslide, etc).

The ground the pool shell will sit on must be properly prepared. If the shell settles you will get cracks.

Also, outside of leaks, what's the average life span for a gunite/concrete pool vessel if properly maintained (I know plaster needs to be resurfaced periodically)

There have been stories here of folks rescuing pool shells that have been filled in or abandoned. Gunite, and rebar should have a long life if properly installed.

 

[shoot_the_goalie]

I have not heard of anyone losing thousands of gallons of water from their pool overnight, if that is what you are asking.

Yeah...I was asking basically if anyone has ever heard of an in-ground concrete pool shell experiencing catastrophic failure like you see above-grounds do, where it collapses and all and/or a large amount of water is released. (In an in-ground concrete pool case, where a large amount of water would be released, causing major shell damage, large soil erosion, mudslide, etc.) Anyway, sounds like it would be a pretty rare event.

 

[JamesW]

The biggest risk of catastrophic failure is floating the pool by draining it when the ground water is high.

Pools typically don't catastrophically fail.

Leaks can happen in any pool.

For concrete, cracks can develop through the shotcrete/plaster or in other places like where the skimmer meets the concrete.

Plumbing can leak in any type of pool.

Concrete pools have a hydrostatic relief valve that can sometimes leak.

 

[techieprof]

Years ago, we had a long period of relative drought followed by recovery with lots of rain. After the rain, a small void opened in the intersection closest to our home. The county repaired it many times as each repair would get swallowed up by the hungry void. Just as I was beginning to have a real concern that we might be at risk for a sinkhole, my neighbor's plaster pool lost around 40% of its water overnight to one. They sold to a flipper who repaired the sinkhole under the pool, but before they completed repairs to the pool and got water back into it, it floated, and that was it. I had a friend in geographic information systems check our area to see if we were at increased risk. She said the problem appeared to be very localized and was unlikely to spread. We stayed, and our home and pool survived. Still miss those neighbors though. I'm glad such problems are very rare!

 

[Dirk]

As you continue to calculate your pool's actuarial tables...

It's the plaster of a concrete pool that is water tight. The gunite underneath is not, it's more porous. The plaster seals around the penetrating plumbing (returns and drains), and up to the tile. The tiles and grout are watertight. Leaks generally occur where two different materials meet: PVC pipe and plaster, metal light niche and plaster, plastic skimmer and plaster, grout and tile, etc. And of course underground plumbing can fail: either a glue joint fails, or PVC is stressed enough to crack. Now if the shell cracks, it's going to take the plaster with it, so I would guess that is the most likely cause of a catastrophic failure. Other leaks tend to be less severe and announce themselves (via slowly dropping water level) way before there is a disaster.

It is risky to empty a pool, as others have pointed out. It can float the pool, and/or compromise the finish. As a concrete pool owner, that is my biggest concern. I've taken steps to eliminate most of the reasons to empty a pool (I'm controlling CH and CYA accumulation). I can't control salt accumulation, so when it comes time to replace water due to too much salt, I'll use the no-drain method of water exchange.