Do I need a Main Drain for my Swimming Pool?

Pool Main Drain

Pool health is a hot and important topic as a pool owner and a suggestion you have probably heard is “Your pool should have a main drain!” Well, what is a main drain, and do you really need one?

Main drains are very normal and common in swimming pools. Inground Pools by code require a main drain but above-ground pools are not required to have a main drain. Although, it is highly recommended that you do have one. Main Drains aren’t just for lowering the water in your pool but are a huge part of pool water circulation. If you don’t have a main drain then you will have to use a sub-pump to clear the water from your pool and rely only on skimmers for pool circulation.

I’ll dive into more information about Pool Main Drains below. If you are looking at an above-ground pool this information is the most interesting for you as the main drain is an option instead of a requirement. Fiberglass pools sometimes do not come with a main drain, which I believe to be a concern because of their reputation for popping out of the ground. Read on to see my thoughts about this to hopefully provide you with enough information to make the right choice during your pool build.

Should I get a Main Drain for my Swimming Pool?

Yes, you should get a Main Drain for your swimming pool unless it is a very small above-ground pool then it may not be worth the extra investment. 

If you are having an inground pool built or you already have an inground pool then you will have a main drain in your pool. It is required by code all across the United States that inground pools require a main drain to be built. 

Above-ground pools on the other hand don’t require main drains and commonly don’t have them installed because of the additional price it adds to the original installation. If you should have one is really a matter of opinion, but in my opinion, I believe the extra investment is worth the added benefits to your overall pool water. 

The addition of a main drain will greatly increase your pool circulation from the bottom of your pool. Skimmers just simply can’t do that from the top of the pool. Just having a main drain in your pool will help keep your pool water balanced, keep the pool floor cleaner, and improve the overall circulation of your pool water. This could also reduce the price of your chemicals slightly which might even out the investment in the pool main drain over time.

The cons of adding a pool main drain into an above-ground pool are the initial investment and the creation of another location in your pool liner that could possibly leak. The price to add in a pool main drain will probably be in the ballpark of $300 – $400. You shouldn’t deal with any leaks if your pool installation team does a proper job, but it is worth noting the risk. If you live in a climate with winter months, blowing out your main drain before closing the pool will also be something you’ll need to learn how to do or pay a professional to help you with. You can check out our article here, to learn how to blow out your main drain as a DIY project to save money.

What is the purpose of the Main Drain in a pool?

The purpose of the pool main drain is to add circulation. This allows the pump to pull water from the bottom of the pool where your skimmers just aren’t going to be able to circulate properly. This increases the health of your pool water immensely and cannot be overstated.

A pool main drain also helps regulate the water level in your pool by quickly allowing you to pump water out directly from the bottom of your pool.

The hydrostatic valve, which keeps the water table pressure under your pool from growing too much and popping your pool out of the ground is located inside the main drain cup. This is an extremely important feature to have for your pool because a pool shell popping out of the ground is just plain brutal to deal with.

Where is the main drain located?

Your pool main drain is going to be located in the lowest spot of your pool.  This is so that it can circulate the deepest water from the bottom of your pool. If you have a completely level above-ground pool then the main drain can sit directly in the middle of your pool at the bottom.

It will look like a grated cover sitting over a gathering pot. This is then connected to pipes under your pool that leads to a pump and the filter. 

If I have a main drain will I still have to vacuum?

Yes, you’ll still have to vacuum your pool but one of the pros of having a main drain is that you’ll have to vacuum less. You can find out more about why that works in my article about leaving your main drain open. The pool main drain will be able to circulate more the sediment and debris that settles onto your pool floor and pull it into your filtration system.

The pool main drain can also create a quick clean-up for pool owners. If you need to get the bottom of your pool cleaned quickly, you can turn up the suction on your main drain. Then after a little while the debris and sediment should gather close to your main drain allowing you to vacuum and clean your pool quickly. 

Do I Need a Main Drain? My Closing Thoughts

In my opinion, as I’m sure you can tell from this article, you should have a main drain in your pool. I believe the pros outweigh the cons immensely. Pool health is extremely important and the main drain is a huge component of pool circulation that you don’t want to leave out of your pool build. In addition, its the location for the hydrostatic relief valve that can help prevent any pressure issues from water table underneath your pool.


The founder of I wanted a place to share all of the great information from my family to other pool lovers, builders, and those looking to buy a pool.

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