Non-return drain gullies - do they exist?

[Simon Roskrow]

I live on the edge of a flood plain, and my rainwater downpipes drain into gullies around the house. Most of the drains then flow to a septic tank, but I can't trace one of them at all and think it flows into a stream or soakaway. When the river rises, water backs up the untraceable drain and out of the gully. I want to find a simple non-return system for the gully, perhaps one with a floating ball in, or one with a manually closable valve. My local builders' merchants and Plumb Center have no ideas, so I'm struggling. Can anyone advise suppliers or stockists, or other solutions? Thanks!

[Tony McC]

You can get non-return valves for underground pipeworks systems, but they are a specialist item, not something you'd find at Travis Bloody Perkins or B&Q.

You'd need to identify what type of pipework you have and then try somewhere such as Burdens, Cooper Clarke, UGS or similar. These are what we call "Civils Merchants" - they supply materials specific to the civil engineering trade (eg: large drainage pipes, manhole sections, road kerbs, ground engineering products) rather than general building materails, such as sand, timber and plasterboard (although some Civils Merchants can supply these, too)

[Simon Roskrow]

Thanks Tony. Cooper Clark stock clay gullies with floating balls in them, which is just what I needed. Cheers.