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Our plumbing terms buster breaks down all the terms you might hear from a plumber and will help you understand more of the plumbing terminology related to water issues in your home.

When it comes to plumbing and drainage, there are two significant differences you need to understand. To make it simple, plumbing relates to clean water, and drainage relates to dirty water. You should call a plumber if the issue is about water coming into your property or call a drainage expert if it’s about water leaving your property.

Use our guide below to get clued up, and ensure you understand the plumbing terms tradespeople use when they visit your property.


Understanding Plumbing Terms

  • Potable supply: The drinking water that comes out of your taps. Water authorities are obliged to provide you with water, and the water is of a specific quality.
  • Airlock: Air in a pipe that prevents water from flowing through it is classed as an airlock. It’s usually in the form of a bubble and can be resolved using pressure from the mains cold tap to force air back into the system.
  • Cistern: The tank used to flush the toilet. These come in different forms; sometimes, they’re bolted onto the back of a toilet, and sometimes they’re fixed to the wall. Concealed cisterns sit behind a wall. If you’ve got a cistern that’s fixed onto the back of the toilet, it’s called a ‘close couple system’. If it’s fixed onto the wall at waist height, it’s called a low-level system, and if it’s raised, it’s a high-level system.
  • Trap: A device that prevents sewer gasses from entering houses. Introduced in Victorian times to reduce the risk of Cholera, there are now various versions available, including ‘P’ traps, ‘S’ traps and Bottle traps. Today, it’s also commonly known as a U-bend.
  • Water hammer: The term used to describe the noise water pipes make when they vibrate. Additionally, a tap that has reached the end of its life will often start banging – this is also described as a water hammer.
  • Bleed valve: The valve which lets air out of a water or heating system. They are often found on radiators and central heating pumps for combination boiler systems.
  • Zone valve: Typically found on non-combination boiler systems, they control the flow of hot water between the different zones in a property and its heating or hot water system.
  • Stop tap: Normally located under a kitchen sink, this is the main isolation point for water when it enters the house, controlling supply to every room.
  • Hot water cylinder: A tank used to store hot water, usually found in the airing cupboard. The tank is usually covered in spray lagging or a red jacket.
  • TRV: This stands for Thermostatic Radiator Valve. It is the automatic temperature control for radiators. Located at each end of the radiator, they have a vented top to let air in. Gas sits inside a bulb within the TRV, which expands as the room gets hot. When a room cools, it expands again to warm it.
  • Lockshield valve: This is also a valve on a radiator that isolates the water supply to it. Simply, it turns a radiator on or off. If you have a leaky radiator, you should turn the TRV off and shut the lockshield valve to prevent further leakage.
  • Microbore: The terms used for the 8mm and 10mm pipework in central heating systems. They use very little water to heat up, meaning you use less fuel and therefore have a more efficient system.
  • Vented heating system: This is the standard term for a non-combination central heating system. It usually consists of a water tank in a loft, allowing water to expand and contract as the system heats and cools.
  • Pressurised heating system: This is related to any heating system that is not vented, such as a combination system.
  • Combination boiler: Provides heating and hot water directly from the boiler, heating water up on demand. Cold water goes into the system and comes out hot.
  • Overflow: A means of allowing excess water from a tank to escape safely. Usually, this consists of a white plastic pipe that comes out of the tank and out of the wall.


Contact Your Local Plumbing Expert

At Metro Plumb, we want to make plumbing terminology simple for everyone. When you call with an emergency plumbing problem, we’ll choose the plumbing expert nearest to you and send out the most suitable engineer for your needs.

Our engineers will always explain your problem clearly, honestly and in simplistic terms, ensuring you understand every step of the repair process before they get started so you know exactly what’s going on.

If you’re experiencing a plumbing emergency, contact us on 0808 250 9949. Alternatively, you can find a local plumber to discuss your plumbing problem in more detail.

11th November 2021   |    Blogs