My pool leaks. How do I find the leak?

[Genady]

Let's start this simple and I will fill in details as needed.

[swansont]

16 minutes ago, Genady said:

Let's start this simple and I will fill in details as needed.

What kind of pool is it? When I was growing up the neighbors had an above-ground pool and the older kids would snorkel in it, looking for holes in the liner. Might also work for cracks in an in-ground pool.

If the leak is fast enough, dye in the water might show a leak.

[Genady]

It's concrete pool, partially in-ground. I SCUBA dove in it to look for cracks. Didn't find any.

Not a very fast leak, about 2cm down of the water level a week. This is about twice of a normal evaporation.

[zapatos]

50 minutes ago, Genady said:

It's concrete pool, partially in-ground. I SCUBA dove in it to look for cracks. Didn't find any.

Not a very fast leak, about 2cm down of the water level a week. This is about twice of a normal evaporation.

I thought my pool was leaking but it was instead the line sending filtered water back to pool. Years of chlorine exposure degraded the pipes. Pool guys who know what they are doing (not just pool guys who know how to open and close pools) can run pressure tests to find if that is indeed the issue.

[Genady]

1 hour ago, zapatos said:

I thought my pool was leaking but it was instead the line sending filtered water back to pool. Years of chlorine exposure degraded the pipes. Pool guys who know what they are doing (not just pool guys who know how to open and close pools) can run pressure tests to find if that is indeed the issue.

OK. How do I find / check this?

[swansont]

10 hours ago, Genady said:

It's concrete pool, partially in-ground. I SCUBA dove in it to look for cracks. Didn't find any.

Not a very fast leak, about 2cm down of the water level a week. This is about twice of a normal evaporation.

When the pool stops draining, you'll know what the height of the leak is.

[Genady]

15 minutes ago, swansont said:

When the pool stops draining, you'll know what the height of the leak is.

I let it go down to the bottom of the skimmer, with no effect. I don't want it to get any lower.

[geordief]

36 minutes ago, Genady said:

I let it go down to the bottom of the skimmer, with no effect. I don't want it to get any lower.

Is the leak costing you any money? If not put up with it and wait for it to get worse when the source  may be more easily seen ? 

 

Is it pure concrete or are there bricks as well?

 

I have a big  outdoor cement and stone  water tank that  fills from the field  but has leaked for the past 25 years as there is a crack half way down at the corner.

[Genady]

1 minute ago, geordief said:

Is the leak costing you any money?

It does. Fresh water is not cheap in Bonaire. It is produced from sea water by reverse osmosis, and we pay by cubic meters consumed.

It is pure concrete.

 

[geordief]

3 minutes ago, Genady said:

It does. Fresh water is not cheap in Bonaire. It is produced from sea water by reverse osmosis, and we pay by cubic meters consumed.

It is pure concrete.

 

If you are sure there are no obvious cracks  then could it be a hairline crack?

Maybe   along where a vertical side meets the floor or one of the other edges? (that is where mine is)

[Genady]

1 minute ago, geordief said:

If you are sure there are no obvious cracks  then could it be a hairline crack?

Maybe   along where a vertical side meets the floor or one of the other edges? (that is where mine is)

I've inspected it on SCUBA vary closely and meticulously. I doubt that I've missed it.

[TheVat]

12 hours ago, Genady said:

Not a very fast leak, about 2cm down of the water level a week. This is about twice of a normal evaporation.

Can there be fluctuations in the evaporation rate?  E.g. would more windy days increase it?  Does humidity drop at some times of year?

[Genady]

2 minutes ago, TheVat said:

Can there be fluctuations in the evaporation rate?  E.g. would more windy days increase it?  Does humidity drop at some times of year?

I measure it quite 'scientifically'. I put a backet of water on the pool side and mark the water level in the backet and in the pool. Later, I compare the change of the level between the two. The pool level goes down about twice faster.

[TheVat]

 Not sure the bucket and pool shape would match, or have same surface exposure to wind and sun.  Maybe different surface to volume ratio. Could you put a tarp or similar covering over pool, see how that effects water level change?

 

 

Edited Wednesday at 02:45 PM by TheVat

[Genady]

1 hour ago, TheVat said:

 Not sure the bucket and pool shape would match, or have same surface exposure to wind and sun.  Maybe different surface to volume ratio. Could you put a tarp or similar covering over pool, see how that effects water level change?

 

 

I cannot cover the pool. I can experiment with 'buckets' of different sizes and shapes. I don't think the difference would be so dramatic. If any, I'd expect that relatively shallow buckets heat up and evaporate faster than the much deeper pool. Plus...

Buckets have the same or more exposure to the sun. The pool is located on the property in such a way that it is protected from winds. Plus...

I am sure that in the last several months I need to add water to the pool about weekly rather than bi-weekly as it used to be for the last 20 years. This was how the project started.

Edited Wednesday at 04:21 PM by Genady

[zapatos]

11 hours ago, Genady said:

OK. How do I find / check this?

You seal one end of the line leading from the pump to the pool, apply pressure at the other end, and measure whether or not the pressure decreases. If the pressure decreases you have a leak in the line. If not, test the line leading from the pool to the filter.

If you do not have the equipment to do the testing you can contact a company that is so equipped.  I used a company that installs pools, as that type of test is normally done by them as they install the lines to make sure all their pipe joints are secure.

[KJW]

I had a pool leak about a year ago. I called in a professional to locate and fix the leak(s). One of the things he did was to get in the pool under the water and place drops of dye near the places where the leak was most likely to be, carefully observing any movement of the dye that would indicate a leak.

 

Edited Wednesday at 04:08 PM by KJW

[Genady]

2 minutes ago, zapatos said:

You seal one end of the line leading from the pump to the pool, apply pressure at the other end, and measure whether or not the pressure decreases. If the pressure decreases you have a leak in the line. If not, test the line leading from the pool to the filter.

If you do not have the equipment to do the testing you can contact a company that is so equipped.  I used a company that installs pools, as that type of test is normally done by them as they install the lines to make sure all their pipe joints are secure.

I do not have such equipment. I will keep this possibility in mind, but it will take time to get them to do this check. And cost. There are four lines: from the skimmer, from the main drain, from the vacuum, and the return. Not the first option on my list.

Thank you anyway.

 

7 minutes ago, KJW said:

I had a pool leak about a year ago. I called in a professional to locate and fix the leak(s). One of the things he did was to get in the pool under the water and place drops of dye near the places where the leak was most likely to be, carefully observing any movement that would indicate a leak.

 

This was one of the first things I did myself (I am a former SCUBA instructor.)

16 minutes ago, zapatos said:

You seal one end of the line leading from the pump to the pool, apply pressure at the other end, and measure whether or not the pressure decreases. If the pressure decreases you have a leak in the line. If not, test the line leading from the pool to the filter.

If you do not have the equipment to do the testing you can contact a company that is so equipped.  I used a company that installs pools, as that type of test is normally done by them as they install the lines to make sure all their pipe joints are secure.

I've just thought of a very simple way to check if the leak is in the pool or in the pipes. I can cover all the inlets and outlets in the pool and see if the leaking stops.

[KJW]

Did you check the waste-water line from the filter (causing loss of water when the pump is on)? This was the first thing the professional checked.

 

[zapatos]

17 minutes ago, Genady said:

I've just thought of a very simple way to check if the leak is in the pool or in the pipes. I can cover all the inlets and outlets in the pool and see if the leaking stops.

Oh, sure. That's a great idea. Very simple.

[KJW]

A difficulty with pool leaks is distinguishing between leaks and evaporation. In my case with a salt-water pool, I replaced the lost water with fresh water until the electrolytic chlorinator stopped full output, indicating a leak and not evaporation (salt doesn't evaporate).

 

[Genady]

22 minutes ago, KJW said:

A difficulty with pool leaks is distinguishing between leaks and evaporation. In my case with a salt-water pool, I replaced the lost water with fresh water until the electrolytic chlorinator stopped full output, indicating a leak and not evaporation (salt doesn't evaporate).

 

This is good, but my pool is a fresh water one. OTOH, I am sure it is a leak, as discussed earlier with @TheVat.

1 hour ago, KJW said:

Did you check the waste-water line from the filter (causing loss of water when the pump is on)? This was the first thing the professional checked.

 

I'm going to check 'pool vs. lines' following this idea:

 

1 hour ago, Genady said:

I've just thought of a very simple way to check if the leak is in the pool or in the pipes. I can cover all the inlets and outlets in the pool and see if the leaking stops.

 

[Genady]

22 hours ago, Genady said:

I'm going to check 'pool vs. lines' following this idea:

 

23 hours ago, Genady said:

I've just thought of a very simple way to check if the leak is in the pool or in the pipes. I can cover all the inlets and outlets in the pool and see if the leaking stops.

 

Only in one day, the effect is clear enough.

I've modified the test from the original idea. Instead of covering all the inlets and outlets, I plugged only the outlets, i.e., the main drain, the skimmer, and the vacuum. The lowering of the water level has slowed down to about the evaporation rate.

Thus, the leak is not in the body of the pool, but in the plumbing between the pool and the filter. This is good news.

Now, how do I pinpoint the leak? The suspected three lines are mostly buried.

[zapatos]

53 minutes ago, Genady said:

Now, how do I pinpoint the leak? The suspected three lines are mostly buried.

Congrats on narrowing it down!

My issue turned out to be the same. And the pipes are under concrete. My pool guy told me that they cannot run a camera because the pipes are narrow and there are generally a number of connections and turns, and since they didn't do the install they don't know the layout. In addition, based on the type of pipe used 20 years ago they know from experience that those pipes break down due to years of chlorine running through them, which is therefore likely the problem. Thus finding and repairing only the leak, even if they can find it, will mean I still probably have a lot of bad pipe that will just leak somewhere else sooner or later.

They suggested digging it up and putting in a new line. Someone else may say otherwise but that was their take on the situation for me.

[Genady]

3 minutes ago, zapatos said:

Congrats on narrowing it down!

My issue turned out to be the same. And the pipes are under concrete. My pool guy told me that they cannot run a camera because the pipes are narrow and there are generally a number of connections and turns, and since they didn't do the install they don't know the layout. In addition, based on the type of pipe used 20 years ago they know from experience that those pipes break down due to years of chlorine running through them, which is therefore likely the problem. Thus finding and repairing only the leak, even if they can find it, will mean I still probably have a lot of bad pipe that will just leak somewhere else sooner or later.

They suggested digging it up and putting in a new line. Someone else may say otherwise but that was their take on the situation for me.

Thank you.

My pipes are buried in the ground around the pool, but not under the concrete. Still, before digging and messing up a big area I'd like to narrow it down as much as possible.