Renovating a Gite in Brittany

At last the terrible smell from the septic tank coming into the house has been solved.

To recap – The septic tank system, with pump and sand filter bed was installed almost a year ago but never really used until we moved into the house in August. Within a few days there was quite a strong smell in the laundry room. The laundry room houses the electric meter, water supply and the main drain to the tank. Fortunately shutting the door kept most of the smell in. Talking to friends they suggested that it just needs a little time to settle and get a crust on the surface of the water in the tank.

Anyway after a few weeks the smell was getting stronger and permeating into the rest of the house. There was definitely something wrong with my plumbing. As a temporary measure I even put a small extractor fan on the outlet for the tumble dryer to suck the bad smell out.

Things didn’t really improve and I spent lots head scratching and pondering trying to work out how the smell was getting back into the house. I checked all the obvious things, like all the traps had water in them, the primary and secondary vents were clear, the soil pipe entered the tank below the water line etc. I just couldn’t understand how the gas was getting in. Maybe there was a pressure build up and the gas was forcing it’s way past the trap for the washing machine. I started imagining the nightmare scenario that somehow I must have cracked or broken a soil pipe under the floor. But even that didn’t really make sense as the smell was isolated to the laundry room and the pipes were buried under the concrete floor.

Anyway to buy some thinking time I decided to leave the lid off the pumping chamber that pumps the waste water from the tank up the garden to the sand filter bed. The pumping chamber has a small electric pump with a float that kicks when the water level rises. It is also vented using the same pipework as the vent for the septic tank. It worked as a temporary solution but sitting outside was not very pleasant.

I was on the point of calling out either the installers of the system or a drain company to send cameras down the soil pipes to find the problem when some friends turned up. After a standing over the pumping chamber bathing in the aroma for a few minutes telling them about the problem, one of them pointed to the red conduit in the side of the pumping chamber containing the electric cable for the pump and asked, ‘where does that go?’

Bing – light bulb goes on. The conduit goes to the fuse box in the laundry room and it was open both ends. All the waste gas was travelling up the electrical conduit straight into the house.

Stuffing a plastic bag into the end of the conduit and sealing the end up with silicon solved the problem. Lid back on, no smell anywhere; fantastic

Sometimes you just get so fixed on one thing (e.g. the soil pipes or my incompetence as a plumber) and just can’t see the wood for the trees!