Plumbing Questions? Ask a Plumber for Answers ASAP
Hello, welcome to the Technical section in JustAnswer; my name is ***** ***** I will help you today.This problem is common in flats and other properties where the supply splits very close to the dwellings.The answer is two-fold:1. Your neighbour has no non-return valve (NRV), or has a faulty one.They should fit/replace an NRV to prevent backflow.An example of an NRV is this one.2. You should install a shock arrestor a short distance downstream of your main stopcock. A suitable product is this one. Even when the pipework is 15mm, I still fit a 22mm NRV to mitigate the restrictive nature of the valve._____If you receive a phone call offer, please ignore it - these are system generated and outside my control. My understanding is that you won't be charged if there's no phone call.