Why Must I Have 2 Main Drains?
If your pool has a main drain, federal regulations require two of them, set at least 3 feet apart, so one person cannot block both.
If you are building a new pool and plan to use a main drain, you need two. This is a safety requirement rather than a design preference.
What main drain entrapment is
Entrapment happens when the suction through a single main drain is strong enough to hold a person against it. It has caused dozens of fatalities.
One of them was the granddaughter of former US Secretary of State James Baker, who drowned in the family hot tub. That prompted the Virginia Graeme Baker Pool and Spa Safety Act of 2007, which mandated changes across the pool and spa industry.
How two drains solve it
Dual main drains are two separate main drains placed a minimum of 3 feet apart, connected by piping to a tee fitting.
The spacing is the point. Set that far apart, one person cannot block both drains at the same time. If one is blocked, the suction shifts to the second drain, and the swimmer can move away freely.
The 3 foot minimum is a build decision. It is set when the pool is plumbed and it is not something you can adjust later.
What the regulations cover
The Act requires anti-entrapment devices, dual main drains, or both, on all public swimming pools and spas, and on all newly constructed residential pools and spas.
It also changed the drain covers themselves. Flat covers were replaced by domed covers with holes in the sides, which are far harder to seal against.
Requirements can vary locally, so check with your builder or your local code office for anything specific to your area.
More on pool plumbing
- Our blog post on why you need two main drains covers this in full.
- See also what the main drain does and whether main drains and skimmers are required for inground pools.
- Browse our inground pool skimmers, returns, fittings and drains.
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