Swimming pool leak detection is simple and can be done inexpensively without hiring someone to come and do it for you.
There are several indicators as to whether or not you have a leak in your pool. The first is that the pool level is dropping unusually fast and you find yourself filling your pool more often than usual at that time of year. Caution. Hot dry days will cause water to evaporate out of your pool and may cause you to think that your pool is leaking. If you live on a hill and your neighbor below complains that their garden is being flooded out, you likely have a leak. The final indicator that you may have a leak is because you have one or several cracks in your pool - either along the sides or on the bottom.
There are three places that your pool can leak. The pool itself, the waterlines moving to and from the pool - both above and belowground, and the pool equipment - the water-filter, the pool pump, the pool-sweep pump, etc. As the ground settles, the pool will shift and crack (this is especially true if the pool has been built in chalky or clay soil or built on a slope). To keep from having future leaks - especially if your pool has been built in any of these conditions, consider installing a vinyl liner.
The best way to check and see if you have a leak in the pool itself is to check the cracks. To determine whether or not the cracks in your pool are leaking, get some dye. The dye can either be from a pool kit that is used to check the chlorine and Ph levels in your pool, one of the chemicals in the kit, or you can use some food coloring commonly found in most kitchens or on the baking aisle in your grocery store. A dark color such as red will be most visible.
Once you have the dye, the first step is to turn off the pool pump. Wait until the water stops circulating. With the use of snorkeling or scuba gear, hop into the pool with your bottle of dye. Get to where you can observe the crack and have no movement of water. Squeeze a few drops of the dye into the water next to the crack and wait a few seconds. If the dye is sucked into the crack, then you have a leak. If it doesn't, then the pool is not leaking from that spot. Move on to another crack. Keep in mind that if the crack you are testing is very deep in the water, and the crack is a minor leak, you may not be able to detect it if you are only using snorkeling gear. Scuba gear is most effective when checking for cracks because you don't need to come up for air, but if you are not qualified to use scuba gear - do not use it. Scuba gear is dangerous if you do not know how to properly use it.
If the pool is free of leaks, check your pool equipment and the pipes that lead to and from the pool. The easiest way to see if the leak is from the pool equipment is while the pump is on. Check to see if water is dripping from any of the pool equipment or above ground water lines. If you don't see any water dripping, wait a couple of hours and then check the ground where the waterlines that return water to the pool are running.
Since pool intake and return lines are near the surface, typically within 12 to 24 inches, a leak on a return line will create a damp spot on the ground that is going to be damper than the surrounding soil, and will typically get muddy a few inches below the surface of the ground. If you are not sure where the water lines run, you can try to find them one of two ways. You can probe the dirt checking for resistance that would indicate a buried line or you can contact your local pool supply company or water sprinkler company and ask them about people in the local area that can be hired to come out to locate and mark where your pool water lines are. Keep in mind that it can be difficult to locate a two-inch water pipe one to two feet underground, so it is usually more efficient to hire out that part to someone with specialized equipment.
Another indicator of a leak is if the pump has to be primed each day when you turn it on. If this is the case, then it is likely that you have an O-ring that needs to be replaced on a valve or the pump. Check for a broken O-ring or one experiencing rubber rot. Bring the O-ring with you when you go to the pool shop for a replacement, or, at the very least, know the brand name of the piece of equipment using the o-ring so that the pool shop can look up the size for you.
If the problem is not with an O-ring, there might be a leak in the water intake line. Typically a leak in the water intake line will suck in air, rather than leaking out water - so this is not the first place I would check for a suspected water leak.
Hiring someone to come out and check for leaks within your pool can be done, but are often very expensive, because they often charge by the hour or by the crack. Rates often go up when the weather is colder. If you hire someone, be sure you understand how he or she will charge you.
Once you have found the leak, it is time to repair. Some repairs can be done yourself and some cannot. Minor cracks in your pool can be repaired using a special epoxy. Some epoxies can be used underwater; some can only be put into a dry area. If you are not good at replacing pipes, hiring someone to replace a leaking pipe might also be in order.
Identifying swimming pool leaks is detective work, but it can be done by the average do-it-yourselfer with patience and perseverance. Remember that pool chemicals are corrosive and equipment will have to be replaced over time. Happy sleuthing!
