How Do I Drain My Inground Pool?

I recently researched and wrote an article about replacing your pool water, then I realized, how the heck do you drain an inground pool?

The easiest way to drain your inground pool is to use the existing pool pump by setting it to suck water from the main drain (not the skimmer) and letting the water go to the “waste” outlet. If your pool doesn’t have a main drain, then you will have to use a submersible sump pump.

There are some very important precautions to take to avoid doing serious damage to your pool by draining it. Let’s see when is the best time to drain your pool and I will consider a few methods for older pools that do not have a main drain and only a skimmer.

Inground Pool Draining Methods

Draining your pool using your existing pump and “main drain”
Most modern pools have a drain at the lowest point of the deep end. This drain is connected via a PVC pipe to a valve in your pump system that switches between drawing water from the skimmer or the pools “main drain”.

Simple find this valve and set it to the “main drain” then leave your pump running on waste. The water will be pumped out of the backwash hose.

Draining your pool using a submersible sump pump.
If you have an older pool without a “main drain” then you will have to make use of a submersible sump pump. You can either hire one from a tool hire shop, or purchase one for yourself.

I recommend you buy one. These pumps are so handy and you will be sure to use it again at some stage, either in your pool or at home. you will also need a long backwash hose.

Here’s a decent sump pump from Amazon: Superior Pump 91250 Utility Pump

Place the sump pump in the shallow and connect the backlash hose with a hose clamp to the outlet. Drop the sump pump in the shallow end of the pool and switch it on. As the water level drops, move the pump deeper and deeper until your at the lowest point of the deep end.

Things to avoid while draining your pool

Draining your pool may be necessary for a number of reasons, and is sometimes unavoidable, as mentioned in one of my previous articles: How Often Should I Change my Pool Water?.

Let’s look at some mistakes that can be made when draining your pool and how to avoid them.

1. Avoid draining your pool after heavy rain.
Do not drain your pool after a lot of rain because the water table may be high and the entire pool shell may pop out of the ground as it essentially floats to the surface of the soft muddy ground.

Be careful even when there has not been any rain recently as a high water table alone can cause this to happen. This can happen to any type of inground pool, concrete, or fiberglass.

If you think that you have a naturally high water table, then it might be necessary to drain only half the water and refilling it.

you might also want to contract the task out to a pool professional who has insurance that can compensate you for the worst-case scenario.

This pool popped out of the ground when it was drained empty after heavy rain. The soft muddy water raised the pool out of the ground as it essentially floated to the surface of the ground.

2. Do not drain your pool in hot summer months.
So you are confident that your pool isn’t gonna “pop”. Now we need to make sure it ain gonna “crack” either.

(pop ‘n crack… This is starting to sound like a rap song)

Draining your pool and exposing the bare concrete or fiberglass to the heat of the sun can cause it to dry out, expand, contract, and cause severe cracks that are expensive to fix.

To avoid this, wait until the swimming season is over before draining your pool. Usually, winter is ideal, and if you can in any way, limit the pool shell’s exposure to sunlight as much as possible while it is empty.

3. Do not leave your pool empty for too long!
As soon as the pool is empty, get to work! For example, if you are draining the pool to scrub the walls, then you should be cleaning the exposed parts as the water line drops so that by the time the pool is empty, you have completed 99% of the work and you can immediately start refilling the pool.

4. Run the outlet hose far away from the pool as possible.
The best place to dispose of the pool water is through a stormwater drain. Some areas allow water to be disposed of onto the street which has their own drains and water control measures.

If you don’t have a stormwater drain or access to a street, you should make sure you drain the water as far away from the pool as possible. If you simply dump all the water next to the pool, you could end up with the same problem as draining the pool after heavy rains, and your pool could end up popping out of the ground.

Also, think carefully about where the water from your pool is going. Do not let the water run into your neighbor’s property. Water can cause serious damage to structures such as retaining walls and foundations.

The water from your pool is your responsibility and you can be held liable for any damage that water causes. Again, this is a good reason to use a pool professional that has insurance to cover these types of problems.

5. Reduce the chemical content of the water as much as you can before.
Pool acid and chlorine can damage many plants and microorganisms that are vital to the wellbeing of the environment. Try your best to get your water neutral before draining the pool by not adding any chemicals to your water well in advance. Your water may start to go green but that will be gone when you replace it with fresh water.

6. Make sure your pool pump is off and unplugged!
Do not let your pump run while your pool is empty! You could seriously damage your pump if you let it run dry. Sometimes so badly that it needs replacing, and pool pumps aren’t cheap.

Read: What Happens If My Pool Pump Runs Dry?

How Do I Get The Last Few Inches of Water Out of My Pool?

Getting those last few inches of water out of the pool can be a pain. Most people simply leave the main drain pulling water while they dilute the last bit of water with fresh water.

You can use a shop vacuum to suck up any leftover water from your pool. If you do not have a shop vacuum, you could hire one from a nearby tool hire store.

Do not simply leave the water to evaporate. You want to finish any repairs immediately and start filling your pool to avoid any damage occurs to your pool shell.

Why Should I Drain My Pool?

You do not have to drain your pool water unnecessarily. Most problems can be fixed with chemicals and some effort, however, there are times when draining your pool is unavoidable.

Typically, you should be draining your pool every 5 to 7 years for the following reasons.

  • Repair cracks or other damages to your pool.
  • To remove calcium buildup in your pool.
  • High TDS (Total Dissolved Solids) in your pool water.
  • High levels of Cyanuric Acid in your pool water.
  • High calcium hardness. (Hard water)
  • Cleaning or resurfacing the pool shell.

If you are confident that you have to drain your pool, let’s make sure you do it safely by looking at some common mistakes made in the past while draining swimming pools.

Factors to consider

Refilling your pool is going to cost you some money, the average pool is around 15,000 gallons of water. For that reason, it might be worth your while to find alternative water sources for refilling your pool.

Your local fire department might fill your pool for you.
One option might include contacting your local fire department. Many fire departments offer pool refilling services at a reasonable fee, and this is going to be your best bet. It is a lot faster than filling your pool with your garden hose and the water should be relatively clean and balanced.

Water Well or borehole water, but there’s a catch.
Another water source you could make use of (If you have it) is a water well or a borehole. Keep in mind that this water might have heavy iron content that will turn to a brownish tea color after adding chlorine. Do not worry because this can be fixed as discussed in my article How to Get Rid of Brown Pool Water.

Water out of the ground might also be “hard” meaning that has high calcium hardness. So if you’re replacing your water because of high calcium hardness, then filling your pool with well or borehole water MIGHT NOT fix your water hardness problem. But also, it might… Therefore, test the water source before making use of it.

It is not uncommon for borehole or well water to smell like rotten eggs thanks to hydrogen sulfide. This is harmless, but honestly is not pleasant! You can fix this easily by triple shocking your pool.

Read my article “Is it OK to Use Well Water to Fill a Pool?” for more information about using well water to refill your pool.

Let’s Wrap This Up

Draining your inground pool can be easy if you have a “main drain”. It is simply a matter of setting the pump valve to draw from this source instead of the skimmer and leave it to run.

If your pool does not have a “main drain” then you will have to make use of a submersible sump pump. You could hire one from a local tool hire shop or purchase one from a hardware store, or even online.

You should avoid draining your pool after heavy rains or if you have a high water table. An empty pool can “float” to the surface of muddy soil, essentially popping out of the ground. This will be impossible to fix and you will have to remove the pool and rebuild it.

The pool water should be directed either to a stormwater drain, the street, or some safe place far away from your pool or any other structure.

Before draining the pool, try to reduce the number of chemicals in the water to reduce the impact that it has on the environment.

You should also avoid emptying your pool during the hotter months because this can cause cracks in your pool’s shell.

Once you have emptied the pool, don’t leave it empty for too long either. Try to do the work or repairs while the pool is draining to reduce the amount of time it is left empty.

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