Pool Water Level: What's Best and How to Adjust

Not every pool owner may realize the importance of maintaining their water level. Whether you’ve got an inground pool or an above-ground pool, or spa, the water level can, literally, make or break your backyard oasis. Too low and your filter and motor may get damaged, too high and it will run inefficiently. The correct water level is around the midpoint of your skimmer. Here’s how to raise or lower your water level and what can happen if it’s too low or too high:
How to Lower Your Pool Water Level
You may need to lower your pool water level after a heavy rain or if you forgot to turn your hose off when filling the pool. To lower the level, you may be able to use the multiport valve on your pool pump or the drain if it has one. If not, you can use an external, submersible pump or siphon the water out with a hose.
Using the Pool Pump Multiport Valve
You can use the waste outlet on your pool pump by switching the multiport valve to the “WASTE” position. If you have another two-way valve on the waste line, make sure it’s open as well.
- Start with your pump OFF.
- Open the two-way valve if there is one.
- Move the multiport valve to "WASTE".
- Turn the pump ON and run until you reach the desired water level.
- Turn the pump OFF
- Move the multiport valve back to "FILTER"
- Close the two-way valve if there is one.
Using the Pump Drain
If your pool has a cartridge filter, you won’t need a multiport valve since you remove and clean the cartridge. If that’s the case, look for a drainage port. Hook a hose up to the spigot, open it, and drain until water is at the desired level.
Using a Submersible Pump
A submersible pump attaches to a hose and sinks to the bottom of the pool. Once there, plug it in and it will begin pumping the water out to wherever you have the drainage set up.
Siphoning Water from the Pool
If you don’t have a multiport valve, drainage port, or a submersible pump, you can siphon the water from the pool if you can create the elevation difference and initial flow needed to start the process.
To create a good siphon, position the exit end of the hose at a lower elevation than the pool, then create the initial suction needed to start the water moving. You can do this by sucking on the hose if it’s empty, or by filling the hose and sealing it with a nozzle until you are ready to start siphoning. When your hose is full of water, with one end in the pool and the sealed nozzle where you want it, remove the nozzle to begin the siphon.
How to Raise Your Pool Water Level
To add water to your pool, you can use a garden hose to raise it to the suggested level—halfway, or three-quarters up your skimmer.
If you need a lot of water added, you may want to contact your local water utility company. Sometimes they will offer an adjusted rate for filling a pool. If you are in an area where public water is very expensive, you may consider finding a water delivery service so it can be trucked in.
When you are done filling your pool, make sure you balance your pool water chemistry since new water will throw off the chemical levels.
What happens if your swimming pool water level is too low?
If the water in your swimming pool is too low, the skimmer can bottom out and suck air into your filter system. And when that happens, you’re at risk for burning out the motor on your pool pump. This could be a costly problem, which is why you should definitely keep an eye on the water level of your swimming pool.
If you’re especially concerned about the level in your swimming pool, consider adding an automatic swimming pool water leveling device. These devices, which are available in a range of price points, typically attach to a garden hose or other water source. They detect when your water gets critically low and automatically fill your pool until the water is back in the “safe” zone. Many pool owners appreciate the extra protection.
Don't forget the spa!
Water levels matter whether you have a pool or spa. If your water level drops in your spa, you’re at risk for burning out the motor and damaging the plumbing system.
What happens if your swimming pool water level is too high?
If your pool level is too high, your skimmer won’t work as efficiently. While this isn’t a very serious problem -- especially compared to what can happen if your pool water is too low -- it can create more maintenance work for you (after all, someone has to pick up the slack if your skimmer basket isn’t catching debris).
In most cases, pool owners don’t need to do much if the water is a little on the high side. In addition to natural evaporation, activities like vacuuming and backwashing can help lower the water level.
Stormy weather ahead? Here's how to prepare.
Preparing for a torrential downpour or hurricane? Don’t drain the pool. Pools were designed to hold water, and you want your pool to be structurally sound during the storm. You can always siphon water out if necessary. Instead of focusing on the water level, focus on making the area around your pool as safe as possible: Move heavy objects (like patio furniture) indoors; disconnect electrical equipment, and give your pool a shock treatment to safeguard the water against contamination.
Maintaining the proper water levels in your swimming pool
Your pool level can fluctuate on an almost daily basis. Everything from evaporation and heavy rains to running your pool pump can affect your pool’s water level. To keep your swimming pool water at the ideal level, it’s a good idea to check your water level daily to ensure that the water level looks normal. You should also keep in mind that routine maintenance activities like vacuuming and backwashing your pool can also lower your water levels, so be sure to add water as needed.