How to detect a Pool Leak - Sutro, Inc

How to detect a Pool Leak

A swimming pool leak can end up being an expensive issue if left unchecked, but the good part is that it is fixable.

These leaks can occur in the most maintained of pools for many reasons. This guide will help you to detect a pool leak, and also how to prevent one.

We'll help you spot most pool leak issues:

Spot a pool leak

If your pool already leaks, it will be visible through several signs.

These may range from changes in the pool water level or visible cracks to soggy spots or an inconsistent pH.   


Test methods to spot pool leaks

You will also learn about the three most prominent test methods if you suspect t a leak.

These include the dye test, bucket test, and pressure test. 


Repairing pool leaks

After the problem has been spotted and acknowledged, you will learn how to repair a pool leak with the most effective and lasting results. 


What Can a Pool Leak Cost Me?

A pool leak can be a minor nuisance in the most benign cases, or it can end up being a really expensive problem that may require extensive repairs.

From making the nearby landscape soggy to lifting/sinking the deck and patio, many problems can arise. 


How Much Water Can a Pool Lose? (Typically)

Generally speaking, a pool with no leaks shall lose a maximum of about a quarter inch of water to evaporation daily.

So that’s about 600 gallons of water per week. Factors, such as weather, pool size, wind, etc., can affect it, but that’s pretty much it for an average-sized pool.


How Much Does That Leak Increase the Water and Electric Bill?

A leak will mean more pressure on the pool refill and circulation system, which raises both the water and electricity bills.

Although, the spike in water bills would not be noticeable unless you have a big leak.

The water bill can almost double in cases of a severe leak, and if you have a heated pool, this number can soar quickly. However, this will also depend on how often you run the pool pump


Other Expenses

A pool leak can cause a grave chemical imbalance in the water, which eventually requires increased use of chemicals and a frequent need for testing.

Both of these will shoot up your pool maintenance budget. 

How to Spot a Pool Leak?

There are many ways to spot a pool leak. These are preliminary checks to give you an idea if you should move forward with detailed checks. 

Signs to Look For:

Here are some common (and uncommon) signs of  a pool leak. 

Visible Cracks

A visible crack on the pool walls is almost a surety that the pool has some leakage.

That’s because cracks take time to grow and they almost always start as a small pinhole. 

Losing More Water than Regular Evaporation

Although smaller drops in water levels are not easy to spot, if your pool water levels are dropping significantly, it can be a pool leak.

You’re Adding Water Very Often

If your pool needs a water refill more than usual, it is a big sign that it may be leaking.

However, you must also take the climatic conditions into account before jumping to a conclusion. 

Air in the System

If you see bubbles coming out from the return jets, it points to a leak in your pool filtration system that could allow water to leak when the pump is not running.

Pool Deck Sinking or Lifting

It is a grave consequence of pool leakage, as the seeping water can cause the construction material to swell or sink.

If you find deformities in your pool deck, always take it seriously.  

Soggy Spots around the Pool

Water from a leaking pool can seep over to the ground in the vicinity of the pool. It can create marshy or soggy spots, or even small water puddles around your pool.

However, this mostly happens when a small pool leak has been left unchecked for a long time. 

Frequent Water Imbalance

A water leak will cause the chemicals to flush out quickly from the pool.

So if you find a sudden and frequent imbalance in the water chemistry (especially the pH) levels, it is almost always a sign of a pool leak. Instead of using test strips and kits for testing the water, you can check out the Sutro pool water monitor.

It runs on battery and syncs live water chemistry data to your mobile app. 

Inexplicable Cloudy Water 

If you take good care of your pool but suddenly find cloudy pool water, this may be a possible sign of a leak. 

How Can I Tell Where My Pool Is Leaking?

Now that you are familiar with the possible signs of a pool leak, you must learn the methods to spot and confirm it.

You can always hire a pool maintenance service, but it is easy and affordable enough to get it done yourself. 

Bucket Test

A simple and preliminary test to spot a pool leak is the bucket test. You’ll need an empty five-gallon bucket (preferably translucent), a weight, and a permanent marker.

Before you begin, ensure it will not rain and nobody enters the pool for another 24 hours. Also, turn off the pool pump. 

  1. Put the weight (brick or rock) inside the bucket and place it inside your pool (on the pool steps), so that the level of water in the bucket matches that of the pool. 
  2. Mark the level of water on the inside and outside of the bucket.
  3. If the level of water inside and outside of the bucket is the same after 24 hours, the pool doesn’t leak.
    However, if the level of pool water is lower than the bucket water, there is a high chance of a leak. 
  4. Repeat the above process with the pump on to see if there’s a leak in the filtration system. 
  5. If you confirm a leak, continue with the dye test. 

Dye Test

The dye test allows you to pinpoint the exact spot of a leak. All you need is a leak finder dye and goggles. 

  1. Spot the signs of a pool leak to narrow down your search area. For example, a crack, skimmer, light fittings, or maybe a wet spot on the ground near the pool.
  2. Turn off the water circulation system. You need the water to be as still as possible. 
  3. Squirt the dye close to the water surface and pool wall at the suspected spot.
  4. If there is a leak, the dye will get sucked inside the leak spot. 
  5. Repeat the above steps for all possible leak spots, and mark them with tape for treatment.

Pressure Test

It is a more technical leak test that requires dedicated tools and some prior technical knowledge and experience.

The technicians charge the pool plumbing lines with pressure and measure the drop to detect leaks. You can learn more about it here

What Are Areas That Often Leak?


Pool liners are very susceptible to leakages, especially vinyl liners if the pool is left dry for long periods.

Proper maintenance and regular checks for the liners are essential to avoid leaks. 


Lack of proper maintenance for the skimmer and pool filter can result in severe damage, which can then become the reason for a leak. 


The pump is the most crucial part of your pool and is also highly vulnerable to leaks if not maintained properly. 

Underground Plumbing

Ruptures in the underground plumbing are also common leaking points for a pool.

These are among the most expensive to repair, and can be identified by wet spots on the ground. 

Do leaks happen more with or without the pump on?

Leaks can happen in either of these situations, and you must run your pump for about eight hours a day for proper water circulation.

The leak can happen on the pressure side or the suction side of the pump. Here are a few signs that’ll help you with identification

> Pressure side plumbing leak

  • Cloudy water in the pool
  • Low flow rate, or the pump is not working properly
  • Frequent need for vacuuming

> Suction side plumbing leak

  • Bubbles coming out of returns 
  • Rapid water loss from the pool
  • Signs of dampness around the suction area
  • Leaking water at the pump connections

How to repair a leak? 

Repairing a pool leak can range from a small plumbing joint replacement to replacing the entire pool pump and filtration system.
Even if the problem looks trivial and fixable on your own, you should seek the help of a pool maintenance expert.

What Options Are Available for Leak Repair?

You may be able to repair a leak on your own depending upon the area in which it has occurred.

It can range from a small plumbing joint replacement to replacing the entire pool pump and filtration system.

Let’s explore the possible solutions for different types of leaks.

Tile Cracks or Fitting Leaks

A crack in your pool wall classifies as a structural leak and can be treated on your own.
You can also encounter a leak near the faceplate, return jets, or pool lights which allow the water to seep through and further compromise the structural integrity of the pool.
There are three methods for a DIY solution:

  • Scrub the cracked area to remove any loose debris and apply some epoxy solution directly to it. Smooth the epoxy and let it sit for about an hour. Check again to see if the leak has been properly sealed.
  • Use a rubber based sealant to fix a tile or fitting leak. Apply it directly using your hand and check again after a few hours.
  • Use a pool putty (or other caulking agents) to seal the crack in the wall

Skimmer or Main Drain Leaks

Leaks in the skimmer can be treated using pool putty as a simple DIY-solution.
However, if the skimmer has started developing leaks, it is best to fully replace it for a permanent solution.
Similarly, the only method to address a main drain leak is to replace it. 

Underground and Plumbing Leaks

Underground leaks are the most difficult of all and can range from a small plumbing joint replacement to busting up the decking to replace a busted pipe.

This is something that does not have an easy fix, and calls for the help of a professional pool repair company.

They will ensure a thorough check, a decisive solution, and the elimination of any possibilities of recurrence anytime soon.

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