Re: I want a smart water meter
Unfortunately, since the Water Fitting Regulations 1999 which brought EU regulations and standardisation into the UK market in order to open up more competition from overseas cistern manufacturers, dump valves and flappers can now legally be fitted. Although most flappers tend to leak too much to satisfy the testing required to gain the EU approval mark dump valves, when tested in the lab, appear to have a life of around 30 years. In practice, the presence of corrosion particles, limescale build up, cistern additives and other water contaminants means that a dump valve will fail far, far sooner than a syphon, and it's most common failure mode is open, leading to increased water loss. This is only tolerated because the same regulations limit the water inlet speed (for reasons of noise), and reduce the volume held in the cistern.