WC pan connectors: the fitting between your toilet and the soil pipe

Behind or under every toilet pan is a short fitting that joins the pan's outlet to the soil pipe that carries everything away. It is called a pan connector. It is cheap, simple and mostly invisible, until it starts to leak. Because the water passing through it has been flushed, a leak here is a hygiene problem, not just a wet floor.

What a pan connector does

A toilet pan has an outlet spigot, a short glazed spout at the back or bottom. The soil pipe, inside the wall or floor, is a larger pipe. The connector bridges the two. One end has rubber fins or a seal that grips the pan spigot. The other end fits into, or over, the soil pipe.

Most UK household soil pipes are 110mm (often called 4in) plastic pipe. Older houses may have cast iron or clay. Pan connectors are made to suit those standard sizes, and the product listing will say which pipes a connector suits. Measure, or check the old connector, before buying.

Types of connector

Straight. For a pan whose outlet points straight back into a soil pipe directly behind it.

Angled. Bends of various angles, including 90 degree bends for a pan that points back into a pipe that goes down through the floor, or the other way round. Some have a small angle to correct a slight misalignment.

Offset. For when the pan outlet and the soil pipe do not line up.

Flexible. A corrugated or flexible section that can bend to make up a gap or an awkward angle. Useful in tight spaces, but it should not be stretched to its limit, sagged or kinked.

Extension pieces add length where the pan sits further from the wall than the old one.

Some connectors also include a vent boss or a branch for a basin waste. Those are part of the wider soil and waste system and are best left to a plumber to plan.

Is it the connector, or the cistern?

Water on the floor around a toilet has several possible sources. Before blaming the connector, narrow it down.

1. Dry everything. Wipe the floor, the pan base and the pipework, and put down dry tissue.
2. Check the supply. Look at the pipe and isolation valve feeding the cistern. A drip here is clean water and appears whether or not you flush.
3. Check the cistern. Look under the cistern, at the bolts and where it meets the pan on a close-coupled toilet. A leak here is also clean water, and often appears slowly after the cistern refills.
4. Flush and watch the back of the pan. If water appears at the joint between the pan outlet and the connector, or at the connector and the soil pipe, as the flush goes through, it is the connector.

A cistern that keeps running into the pan, or out of an overflow, is a different problem. See our running toilet guide and toilet fill and flush valves.

Why connectors leak

• The pan has moved. A loose pan rocks slightly every time someone sits down, and the seal works free.
• The seal has perished or hardened with age.
• Wrong size or poorly seated. A connector pushed only part way on, or the wrong type for the pipe.
• A partial blockage further down makes waste back up and push past the seal. If the toilet also drains slowly, see blocked toilet.
• A cracked pan spigot, which no connector will fix.

Fixing it: what to expect

Replacing a pan connector is a common plumbing job. It usually means turning off the water to the cistern, emptying the cistern and the pan, unfixing the pan from the floor and wall, pulling it forward, removing the old connector and fitting the new one. Then everything goes back, is fixed firmly and tested with several flushes.

It is messy. The pan and connector will have waste water in them, and the old connector may be stuck. Wear gloves, protect the floor and have a bucket and old towels ready. If the pan is close-coupled to the cistern, it may need to come off with the cistern attached, which is heavy.

Call a plumber if:

• the soil pipe is cracked, loose or old cast iron or clay with a perished joint;
• the pan is cemented or tiled in;
• you see damage under the floor or on the ceiling below;
• the toilet also has a blockage you cannot clear;
• you are not confident lifting and refitting the pan.

Pan connectors at Wickes

We haven't tested this. Figures are as the maker states them (checked 13 November 2026).

Can I seal a leaking pan connector with silicone?

It might slow a weep for a while, but it is not a proper repair. The seal is designed to grip the pan spigot on its own. If it leaks, the connector, the pan fixing or the pipe needs attention. Our sealant and silicone guide explains what silicone can and cannot do.

Why does my toilet leak only when flushed?

That points to the outlet side: the pan connector, the joint with the soil pipe, or the flush pipe between cistern and pan on low level toilets. A leak that appears without flushing is more likely the supply or the cistern.

Does a new toilet need a new pan connector?

Often, yes. A new pan may sit at a different height or distance from the wall, and an old connector's seal is unlikely to grip a new spigot as well. Check the new pan's outlet position before buying.