In our tests of single- and dual-flush toilets, the ones with the ... deliver more thrust in our tests than those with a 2- to 2½-inch valve. Ask to see the manufacturer’s specifications ...

The seat disk predates the Korky flapper, so your toilet must be really old if it has a flush valve ... dual-flush toilets,” Barnes says. “This gives us the ability to have a No. 1 and a No. 2 ...

That means some 400 million litres of water leak from U.K. toilets ever day — enough to supply 2.8 million ... the flush mechanism. Dual-flush toilets usually have a mechanical valve with ...