Pool Pump Drain Plug: Location and Winterizing

What a pool pump drain plug is

A pool pump drain plug is a small threaded fitting set into the pump housing, usually on the lower part of the body. When removed, it opens a hole that lets water drain out of the pump. On a product listing, sellers may call it a drain plug, a winterizing plug, or a drain cap, and may list it under features or show it in the image set.

The plug is part of the wet end of the pump, the section that holds water as it moves from the strainer basket to the impeller and out the discharge. It is separate from the strainer basket lid, which you open to remove debris, and separate from the plumbing unions that connect the inlet and outlet pipes. The article on the pool pump strainer basket explains that opening.

A listing may not state the drain plug at all. Model names and feature bullets vary by seller, so the absence of the words "drain plug" does not mean the pump lacks one. The image set usually shows the lower front of the housing, and the maker's manual is the place to confirm the plug's position.

Where the drain plug sits on the pump

On most pumps, the drain plug is at the bottom of the pump housing, below the center line of the impeller. That position lets the housing empty when the plug is removed, because gravity pulls the water toward the lowest opening. Some models place the plug on the lower face of the housing, near the base; others place it on the underside, which you can only see when the pump is raised or tilted.

Both inground and above ground pumps can have a drain plug, but not every model does. A compact above ground pump may have a simple plug; a larger inground pump may have a threaded plug with an o-ring. The o-ring is a replaceable part, and the maker's manual lists its size.

When you read a listing, look at the side and front images, not just the main view. If the seller photographs the pump from several angles, the drain plug is often visible at the lower front. The written description may name a drain plug in the specification table.

Why the drain plug matters in freezing weather

The drain plug exists mainly for cold weather. Water expands when it freezes, and a pump housing that is full of water can crack when the water turns to ice. Removing the plug allows the housing to empty, which removes most of the water that could expand.

This is a product care matter, not a performance feature. A pump with a drain plug is easier to prepare for a cold spell, but the actual winterizing procedure is set by the maker. The manual for your model states whether the plug must be removed, whether the housing should be partly drained or fully drained, and when to do it relative to the first frost.

Pool pump winterizing covers the bigger picture for the whole pump. For the plug itself, the manual's diagram is the reliable guide because no two housings place the plug in exactly the same spot.

Drain plug versus other pump openings

The drain plug is one of several openings in the pump housing, and it helps to keep them separate when reading a listing. The strainer basket lid opens the front chamber where debris collects. The inlet and outlet unions connect the plumbing. The drain plug is the opening whose only job is to let water out, not to move water or hold debris.

The pump's drain plug is not the drain at the bottom of the pool. The pool floor drain is part of the pool shell and the suction system, and it has a different purpose. A listing for a pump will not refer to the pool floor drain; the words "drain plug" in a pump title apply to the fitting on the pump body.

Some listings bundle a drain plug with a hose or an adapter. Read those as the seller's words: the bundle tells you what is in the package, not how the plug is installed.

Reading a listing for drain plug details

When you shop for a new pump and want one with a drain plug, look for three things in the listing: the feature line that names the plug, the image that shows the lower housing, and the specification table that lists the plug type. Not every listing provides all three, and the absence of one does not mean the pump lacks it.

The maker's manual is the final authority. Hayward and Pentair, for example, publish manuals for their pump lines, and the manual's parts diagram labels the drain plug and its o-ring. The article on pool pump housing material explains how the housing itself is described in a listing, which is useful context when you compare models.

If the listing is for a refurbished or open-box unit, the drain plug may be missing. A listing for a refurbished pump often states what is included, and whether the plug is present is a question to read in the listing and confirm with the seller before buying. When you compare full models, the best variable speed pool pump guide lists models by stated features, and the best above ground pool pump guide covers that pool type.

A quick checklist for the drain plug

Use the list below when you compare listings and read the manual. It keeps the drain plug in view without replacing the instructions that come with your pump.

• Find the drain plug in the maker's manual diagram before you commit to a model.
• Read the listing's feature line and image set for the words "drain plug" or "winterizing plug".
• Confirm whether the plug has an o-ring and whether the manual names it as a separate part.
• Use the manual, not a general article, for the timing and removal procedure.
• Remember that the plug is only one part of preparing the pump for cold weather; the whole procedure is in the manual.

What to pick for your situation

Questions

Where is the drain plug on a pool pump?

Usually at the bottom of the pump housing, below the impeller center line. Some models place it on the underside, visible only when the pump is tilted. The maker's manual diagram is the most reliable way to find it on your model.

Do all pool pumps have a drain plug?

No. A listing may not name one, and some compact pumps do not have one. If the drain plug matters to you, look for the words in the listing or in the maker's manual before buying.

Why does the drain plug matter in winter?

Water expands when it freezes. A housing full of water can crack when the water turns to ice, and removing the plug lets the housing empty. The manual states when and how to drain your model.

Is the pump drain plug the same as the pool floor drain?

No. The pump drain plug is a fitting on the pump body that lets water out. The pool floor drain is part of the pool shell and the suction system, with a different purpose.

What should you look for in a listing that mentions a drain plug?

Read the feature line and the specification table, and check the image set for the lower housing. If the listing is for a refurbished or open-box pump, the plug may not be included, and the listing should say so.