blocked drain, and clogged interceptor trap

18 Oct 2004
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United Kingdom
Hi all

Every few years I get a blocked main drain, I think primarily because the system is quite old, and includes an interceptor trap where the drain presumably enters the main sewer.

The situation is the drain is partially blocked, though it does drain slowly after putting a tub of caustic soda down it. The rodding eye of the trap is clogged with crud. So I'm not quite sure how to proceed with rodding it. Should I try to force the crud in the rodding eye down through the trap, or should I try rodding through the manhole cover which is about 20 meters from the trap.
Or flush more and more caustic soda down the drain

Any help would be appreciated


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Does said drain serve more than one property? If so, down to Sewerage Undertaker to sort out now, (law changed on 01/10/11). Interceptors are often cause of problems, however the Victorians had their reasons for using interceptors, and they did bring about great advances in sanitary engineering so cant really hold it against them. ;)

If you need to proceed yourself, i'd avoid the chemical route, caustic soda will probably have little effect in a sewer. Rods are way to go, just be careful after putting that caustic soda down there, it'll take no prisoners. Gloves and goggles are a minimum, this is your last pair of eyes...... :!:

Break crud up with the rods, flush through with copious amounts of water. The sewerage should flow through the interceptor trap. The rodding eye should either be fitted with a stopper or left open, if water is flowing out through the rodding eye then the trap is blocked and needs clearing.
Get it jetted out for a fixed price, once clean, it should stay clean as long as no fat, oil, ear buds, sanitary towels, make up towels, kitchen towels/paper or baby wipes go down the toilet. You will be surprized what I find in manholes.

The rule is: Only what comes out of us and toilet paper.


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