Common Problems with InGround Pools

Inground pools are beautiful, and not as difficult to maintain as many would believe. However, there are some common problems with inground pools and not-so-common ones. Some of the common issues for in-ground pools are low water pressure at the returns and air in the system; specifically, air in the filters and motors. Thankfully, a less common problem for in-ground pools is plumbing leaks. However, they can happen, and it’s a good idea to figure out if it’s happening and where it’s happening as soon as possible. Losing just an inch from the top of your in-ground pool could mean up to five-hundred gallons of water being lost, which can cause some serious complications on your property and neighboring properties.

Read on about how to diagnose the more common issues with in-ground pools, as well as how to repair them, or if you need to contact a professional.

Low Water Pressure at the Returns

The piping on pool systems for in-ground pools has two sides – the suction side before the pump and the pressure side after the pump. The pump makes a vacuum that will suck water from the pool and push it back into the pool through filters. A leak in the suction is going to make the air suck back into the system. Leaks on the pressure side will make water spray. If there is a blockage on the suction side of the pump, it will restrict the amount of water going to the pump, which results in low pressure. Blockages on the opposite side will cause the opposite effect – high pressure.

Clogged Skimmer Basket

One of the most common causes of low water pressure at the returns is a clogged skimmer basket. If the skimmer basket is full of gunk, then you’re shutting off the pipe between the skimmer and pump. This reduces the flow of water, and when the pump has less water going into it, then it moves less water out of it. The solution is simple. Clean the skimmer basket.

Clogged Strainer Basket

Another common built-in pool problem is a clogged strainer basket. Clogged strainer baskets mean less water going to the pump, which means less water pressure coming out at the returns. Clean the strainer basket by removing the debris on it.

Clogged Filter

Further on down the line, a clogged filter can cause low water pressure at the returns. If the water cannot get through the filter, then there is less water flowing out of it. This can increase the pressure on the filter, which means it’s time to clean it. Wash the cartridge filter and soak it overnight in a TSP solution to get all of the grease out of the folds. Grease can be caused by suntan lotion, pine tree needles, and the sebum from people’s skin. For a sand filter, backwash appropriately and change the sand every five to seven years.

Too Many Features

One of the less common issues, but still one that can happen, is too many features being open. Your in-ground pool pump is only meant to move so many gallons per minute. Too many water features, such as sprinkler systems and hoses, will reduce the pressure at the returns. Alternate between what features are being used, or replace the pump motor with a larger one.

Air in the System

An in-ground pool’s filtration system has two sections – the suction side and the discharge side. Check the strainer pot of the pump. If there are a lot of bubbles moving through the strainer pot, then it’s clear the air leak is coming from somewhere on the suction side of the plumbing. See Video

Check Water Level

The first step is to check the water level of the pool. This is the most common, and easiest to fix, complication. The water level should be halfway up the skimmer’s intake. If it’s below that level, then the skimmer will suck air into the skimmer pipe and into the pump. The solution is simple. Fill the pool to the halfway point of the skimmer and check for anything that is holding up the flap of the skimmer.

Strainer Lid

If the pool’s water level is fine, then inspect the strainer lid for the pump. If it’s not on tight, air can be sucked in around the lid. Check the lid, but be sure to flip the breaker switch to turn off the power to the pump before handling anything.

Remove the pool pump strainer lid. Pull the O-ring from the groove and clean any dirt that might be on the O-ring or in the groove. Inspect the O-ring for signs of wear. It may need to be replaced. Lubricate the O-ring lightly before you replace the lid. Use a seal lubricant, such as silicon or Teflon, not petroleum jelly.


If the strainer lid wasn’t the issue, then check the union inserted before the pump. Make sure the power is off before you unscrew the union. There should be an O-ring in the union’s groove. Check this one for signs of wear and tear or dirt, and clean it or replace it. Lubricate the O-ring, recouple the union, and tighten it only with your hands. If you overtighten, you could damage the O-ring.

Motor Shaft Seal Leak

If these steps didn’t solve the bubbles, and you’re working with an older pool pump, there could be a leak in the motor shaft seal. Replace it using the manufacturer’s instructions. Another source of leaks can be the motor’s drain plug on the suction side. If this plug is loose, tighten it.

Plumbing Leaks

Above-ground pools are easy to detect a plumbing leak in because they’re usually very visible; however, inground pools have plumbing beneath the ground, which can make it much harder to figure out if you have a leak in the plumbing. The first step with a plumbing leak is to determine if there is actually a leak.

Determining If There’s a Leak

First, find an empty five-gallon bucket. Place it on the second step of the pool. Fill it with water to match the pool’s water level, and use a piece of duct tape or a permanent marker to mark the level inside the bucket. Turn off the pump for the pool, as well as any auto-refill devices you might have. Wait twenty-four hours, and compare the pool water level to the level in the bucket. If they have both gone down, but are still even, then you’re losing water to evaporation. If the water levels are different, then you have a leak somewhere in the pool or in the plumbing.

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