New drainage run

[alanthomaswatson]

Folks

Not sure if this forum covers underground drainage but can't see where it would go otherwise.

I'm looking to have a new drainage run installed to collect rainwater from one r/w pipe at the front of the house and collect the flow from a washing machine in the cellar (about half way along the gable end and pumped via a Sani) and connect to the existing combined drain at the back of the house.

The total run is about 12m being one 1m length, 90 deg turn, 9m length, 90 deg turn, and one 2m length connecting into the drain at the back of the house.

Basing the trench depth as 550mm and allowing for siting the pipe on 100mm pea shingle can anyone give me an idea of budget figures?

Trench wall supports would be needed as the run would have to be close to my garden wall.

Any help much appreciated.

 

[Agile]

People involved in plumbing understand whats involved but most new drainage is now fitted by builders!

My immediate response is thet its against the regulations for washing machine waste to be directed into a rain water drain!

Big fines can be levied for pollution of water courses where surface water drains usually discharge.

Tony

 

[alanthomaswatson]

Tony

Thanks for the quick response.

I'll try this in the general building forum,

As I understand it, it's allowed as I have a combined drain anyway (house is late Victorian) so it's not making any difference to the current set up.

 

[Agile]

Whilst the builders mostly install new drainage its plumbers who understand it and know the regulations.

I had overlooked that you said it is a combined drain.

If you have 90° bends then an inspection chamber is recommended at changes of direction.

I dont do drainage instals for my customers but would suggest about £30-£60 per meter plus £220 per inspection chamber plus £300 to cover overheads.

You dont say where the front of house rain water currently goes.

It would be far cheaper to fit an above ground 32mm pipe around the outside wall of the house or better cross the cellar internally if it covers the whole of the house.

Tony

 

[Richard C]

As I understand it, it's allowed as I have a combined drain anyway (house is late Victorian) so it's not making any difference to the current set up.

You need to check specifically with your Local Authority; even though you have an existing combined drain, most water utilities won’t allow a new surface water connection unless there is no other option.

If they do, the work is subject to Building Notice submission, inspection & possible witness test & there is a fee involved. You must have access from one or the other for clearance of blockage & are allowed one change in direction up to 45 degrees, then you need an inspection chamber. Prices are impossible to give on a forum as it’s subject to local conditions so get some quotes but with those changes in direction, you could be in for a surprise!

 

[alanthomaswatson]

Thanks for the replies.

As regards the building regs notice, i thought this was required for any connection to a new drain whether foul or rainwater.

If it means not applying for building regs I'd happily take out the r/w pipe connection.

This would also reduce it to one inspection chamber.

 

[Richard C]

As regards the building regs notice, i thought this was required for any connection to a new drain whether foul or rainwater.

Yes it is; it’s also required for a Saniflo connection into an existing stack system but many don’t bother; I see you’re only using it as a pump for the w/m, is connecting to an existing stack not an option? Surface water is mostly drained through a soak away now which are also subject to BR’s & notifyable but many don’t bother; just make sure it’s big enough & at least 5m from your property.

If it means not applying for building regs I'd happily take out the r/w pipe connection.
This would also reduce it to one inspection chamber.

Won’t help I’m afraid.

 

[alanthomaswatson]

Richard

Thanks again. It would be possible to run the Saniflo under the floor but it works out at 6m run back to the stack at the back of the house. The house has a cellar under the front but just a sub-floor under the back. I have enough of a drop to get about a 2 deg run for the pipe out from the Saniflo and I know the Sani only requires 1 deg but I'm a bit dubious at such a shallow flow.

With a long run I need a few joints in the pipe and if their under the floor and inaccessible it'd be a hell of a mess to repair.

Plus the Mrs doesn't want me to lift the dining room floor!

Is it possible to get 32mm waste pipe in 7 meter lengths or longer?

 

[Richard C]

Is it possible to get 32mm waste pipe in 7 meter lengths or longer?

You can get 110mm soil in 6m lengths but not sure about waste, mostly it’s 3m. Joints are really not a problem if you use solvent weld, they are as strong as the original pipe but if you’ve any bends, you obviously need access in case of blockage.