Do I need a Double Check Valve for a Garden Tap?

Hi All, I am looking to install a new garden tap at home. Some have told me that I would need a “double-check valve” fitted for the water supply, to prevent freezing the valve in cold weather. Is this an absolute requirement? Would this mean that I would have the valve inside the house and then use a garden tap that does not contain this valve inside it?
Are there any problems in using a tap with a check valve built-in, instead? IE – could it still cause freezing during cold weather? Any advice would be appreciated!

Asked by Jackie on 2nd Mar 2019
Expert Trade Answers
"Water regulations stipulate that you must have a non-return valve ie check valve to prevent back flow and water contamination. An isolation valve is not a legal requirement but is a good idea for the winter to turn the water off to the outside tap to prevent frozen pipes."
Answered on 2nd May 2019 - Member since Nov 2018 - report
"Check valves are uses to prevent a back flow of water reaching the water mains system (which is required for water regulations anyway). They can be vulnerable to damage from frost, so it is best to have one fitted inside your property. The double check valve should be leading from the main supply, to the garden tap – if this is the case then this would be correct. "
Answered on 2nd Mar 2019 - Member since Mar 2019 - report
"A check valve will not prevent freezing however it prevents any back flow of water into your plumbing system
I would suggest you install a tap with built in check valve."
Answered on 7th Aug 2019 - Member since Aug 2019 - report
"Hi,

Absolutely use a double check valve. Double-check valves aren't to stop freezing, they are to stop backflow, therefore contamination of water. To stop freezing use an isolation valve to turn the outdoor tap off in the winter, and insulate the outside pipework if needed."
Answered on 18th Oct 2019 - Member since Aug 2019 - report
"Check valves tend to not prevent freezing but they do prevent any backflow of water into the system, installing a tap with a built-in check valve would be advantageous. Hope that helps."
Answered on 28th Feb 2021 - Member since Dec 2020 - report
"Fitting a check valve will not stop it freezing it stop the back flow from what ever is in the hose that could contaminate your inside tap water. Outside taps can come with check valve in already. So yes always fit a check valve"
Answered on 17th May 2019 - Member since May 2019 - report
"A Check valve is a non return valve, it is essential to have this fitted to an outside tap to stop the possibility of back flow and potentially contaminated water from outside re entering the potable water in your taps."
Answered on 22nd Jul 2019 - Member since Jun 2019 - report
"Yes, you must have a check valve either in the tap or in the pipework from the mains to the tap. This is to stop back feed of stale or contaminated water."
Answered on 31st May 2019 - Member since May 2019 - report
"You MUST use a tap with a check valve they are inbuilt into the tap so not a separate item, fit an isolation valve inside the property so you can turn off in winter if needed. If you do open the external tap to drain the small amount of water lodged in the tap body."
Answered on 19th Jul 2019 - Member since Jul 2019 - report
"Its more about back flow of some thing in garden ie paint or any thing the hose may accidentally be left in
Its a good idea to add"
Answered on 1st Sep 2019 - Member since Aug 2019 - report
"Hi,

Using a check valve within the tap is apparently against regulation but it still does the same job. I think more because it is only a single check valve and you require a double check valve. if you're worried about the tap freezing a bursting in the coming winter then i also recommend a isolation valve so you can turn it off in winter."
Answered on 1st Aug 2019 - Member since Jun 2016 - report
"With or without check valve you may still get freezing. A double check valve is to stop back flow of water contamination"
Answered on 17th Aug 2019 - Member since Oct 2018 - report
"Fit a service valve inside, during extreme weather
Close service valve and open outside tap slightly"
Answered on 30th Apr 2019 - Member since Jul 2018 - report
"A check valve doesn’t prevent freezing, it prevents contamination of the water supply caused by back flow. A check valve on a garden tap is a requirement of the 1999 water Regulations. An isolation valve inside the property would enable you to shut off the water supply to the tap in winter helping to prevent the tap freezing.
Hope this helps"
Answered on 29th May 2019 - Member since Aug 2018 - report
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