Drain Query

[Billy_s]

I removed a drain cover just next to a plastic down pipe and found that it was full of soil (see picture attached). I wasn’t sure if the soil had collected in the gutter over the years and had been washed down or whether it had been deliberately placed there.

I excavated the soil that was sitting in the drain and discovered that the drain seems to link to the plastic downpipe as about 18 inches/ two feet under ground level, there was an opening facing the plastic downpipe. I also filled the drain with water and found that it only drained as far an an opening.

I have two questions. We’ve been in this house (a Wimpy late 60s build), for 14 years and haven’t had any drainage problems. Is the drain (that was previously packed with soil) serving any purpose? If not, should I just replace the soil (or fill it with pea gravel), on the grounds that if ain’t broke don’t fix it or leave it empty?

Hope I’ve explained this clearly and would welcome your advice.
Thanks

 

[Harry Bloomfield]

From what I think I can see in the bottom of the hole, it connects to the fall pipe directly adjacent to it at the top of the picture. What is the fall pipe for?

What did you mean by - "I also filled the drain with water and found that it only drained as far an an opening."?
What opening is that?

The pipe and water should flow briskly away and into a manhole, is there a manhole inspection cover in the area?

 

[Billy_s]

Beginning to wonder if it’s a redundant drain (which might explain why it was filled with soil?). I’ve run a hose again and the water is just lying. There is just one opening in the excavated pipe and this faces in the direction of the house wall where the plastic downpipe that collects rainwater from the gutter is clipped. Can’t see any manhole covers other than the big one on the picture where I've previously seen flowing water when the kitchen sink has been draining.

 

[Hugh Jaleak]

Looks to me like a 'Back inlet gulley'. Opening towards the house is the connection from the downpipe in the picture, bringing the rainwater down from the gutters I assume. The pot should have a certain amount of water in the bottom, this acts as the trap, sealing off the gulley from the sewer, and preventing any odours escaping. Pot may look something like that in the picture, you wont see the outlet as it's buried & not visible unless all the water is removed.

 

[Billy_s]

Many thanks. Yes, that’s what it seems to be. I was surprised at the amount Of soil in the gully. It was full to the top of the cast iron cover. It was almost as though it had been filled in deliberately. Having said that, when we cleaned our gutters we couldn’t believe how much soil had collected. There were even weeds growing. Don’t know how it gets there.

 

[Leofric]

As others above suggest , isn't it just a gulley that has filled with silt . The gullies in my shared tarmac drive fill with silt / leaves and need cleaning out every year by taking the grilles off and scooping the crap out with my hand.

 

[Billy_s]

Yes. I was just surprised at how much soil was in it. The opening in the gully that faces towards the house was also clogged so i’ll try and get a rod into it tomorrow. The house must be about 50 years old so maybe it has never been cleaned before.

 

[scbk]

Looks like the downpipe has an access point/rodding eye, open that and stick the hose down to flush it through.

 

[Billy_s]

Thanks. Tried to remove it this afternoon but it felt like it was glued on. Will see if I can turn it with some builders gloves on to get better purchase.

 

[Hugh Jaleak]

Dont force it, if it doesn't want to come undone, it may either break, or wont seal again. I'd poke a hosepipe up from the gulley and see if you can wash as much silt out as possible from that end. Wickes do a decent Wet Vac for about £40, invaluable for this type of work if you can get one.

 

[Billy_s]

Thanks again . The plastic cover looks like it has been glued on so I’ll do as you suggest. It was clogged in the gully pipe facing the house.I got as much out as I could using a garden trowel so will try the hosepipe to try and dislodge the rest of it.

 

[Billy_s]

Thanks for your replies.

A quick update. Today I had time to have another look at the down pipe and gully. Instead of removing the plastic cover I was able to detach part of the down pipe. This gave me access the bottom part of the down pipe where water from the gutter would enter the ground. I had a good prod with a rod and this confirmed that the connection between the down pipe and the ground level gully opening was clear. I had expected that there would be another connection leading off to an underground drain but couldn’t feel anything. I gave it a good prod with a rod (from both the gully and down pipe direction) and also blasted it with a power hose. The connection between the downpipe and gully seemed smooth and I couldn’t feel any blockages or additional connections.

What I did discover when using the hose from the downpipe end (to simulate rainfall from the gutter), was that water just collected in the gully and would have overflowed if I had kept the water running. It seems that the purpose of the gully is just to allow water to overflow and discharge onto our drive which is on a slope? Would this make sense? As mentioned earlier, the house was built by Wimpey in the late 60s

 

[bobasd]

OP, read whats been said in the thread just above yours in the forum "pipe to nowhere" and read similar threads below on this page.

 

[Leofric]

It seems that the purpose of the gully is just to allow water to overflow and discharge onto our drive which is on a slope? Would this make sense?

Wouldn't make sense to me, it should discharge to a drain .

 

[bobasd]

fwiw: the clay gulley shown in the pic above looks like a P-Trap gulley not a BIG back inlet gulley