Dishwashers are among the most convenient home appliances, but their installation requires careful attention to plumbing—especially the water supply. Whether you're installing a new dishwasher or upgrading an old one, knowing the correct type of water connection is essential to avoid leaks, maintain performance, and comply with UK plumbing regulations.
At Citywide Plumbers, we handle dishwasher installations all across London and ensure your appliance is safely and professionally plumbed in. Here's what you need to know about the water connection side of things.
1. Cold Water Connection is Standard in the UK
Most dishwashers in the UK are designed to connect to a cold water supply, not hot. That’s because modern machines heat the water internally to the right temperature, making a cold feed the safest and most efficient choice. Citywide Plumbers connects dishwashers directly to the cold mains water supply using WRAS-approved fittings.
2. Pipe Size and Type
The cold water feed should be a 15mm copper or plastic pipe, commonly used in British plumbing. This pipe must be easily accessible and close to where the dishwasher will sit. If the pipe isn’t already in place, our plumbers can extend it discreetly behind units or along skirting to create a neat connection.
3. Use of a Flexible Hose
A flexible braided hose, often supplied with the dishwasher, is used to link the appliance to the isolation valve. This allows for slight movement of the dishwasher without putting stress on rigid pipes. At Citywide Plumbers, we always check the length and quality of the hose and replace it if necessary to ensure it won’t kink or split.
4. Isolation Valve for Safety and Maintenance
An isolation valve is a small, manual shut-off valve that allows you to turn off the water supply to the dishwasher without affecting the rest of your kitchen. This is particularly useful during maintenance or emergencies. We always install a clearly accessible isolation valve as part of every dishwasher plumbing job.
5. Water Pressure Considerations
Dishwashers operate best within certain pressure ranges. If the water pressure is too low, the dishwasher may not fill properly. If too high, it could cause wear and leaks. Our team checks the pressure during installation and can fit a pressure-reducing valve or booster if required.
6. Backflow Protection
To comply with UK Water Regulations, a non-return valve or air gap must be fitted to prevent dirty water from flowing back into the clean supply. This is an essential safety measure, and all Citywide Plumbers installations include proper backflow prevention.
7. Avoid DIY Shortcuts
While connecting a dishwasher might seem simple, using the wrong type of pipe, valve, or connector can result in costly water damage. At Citywide Plumbers, our engineers are trained to ensure all fittings are compliant, secure, and installed with precision.
8. Future-Proof Your Plumbing
Thinking of upgrading your kitchen in future? We can install additional outlets and shut-offs to make adding or relocating appliances easier. Our plumbers advise on best layouts, saving you time and money on future renovations.
Whether your kitchen already has a cold water feed or needs a new one installed, Citywide Plumbers is here to make the process seamless. We provide reliable, regulation-compliant installations and full testing before we leave your home.
Call 02038928545 or email info@citywideplumbers.co.uk to book your dishwasher installation with a team that puts safety, service, and quality first.