Washing machine waste pipe across the kitchen

[Terry]

I want to install the washing machine in the kitchen but the only suitable place is under the worktop on the opposite side of the kitchen to the sink. What to do with the waste is the problem.

The soil stack is behind the sink and the only access to it is via the existing sink waste pipe through the wall via a short stub which connects directly to the sink trap. A slimline dishwasher under the draining board is already connected this waste system.

The kitchen has a suspended floor and the horizontal distance from the washing machine to the sink would be 3.5m (measured wall to wall).

My idea is to modify the sink waste to provide an extra spigot as normal, then connect a short length of hose to a vertical pipe down through the floor, across the kitchen, then back up again at the washing machine end, connecting onto the WM exhaust hose.

The vertical lift at the WM end would be a few cm less than when it's draped over the edge of the sink now. It would also be about 15 - 20 cm higher than at the sink end. By my reasoning the pump would not have to work any harder as at present as far as the vertical lift is concerned as the lift at the far end is more than compensated for by the drop at the beginning. Extra effort would, of course, be required to transport the water horizontally.

When I did a search on this site I found suggestions of Saniflo pumps and 32mm pipe which seems like overkill to me, especially as the remote end in my case will connect via the standard hose spigot onto the sink waste which, of course, is nothing like 32mm!

What would happen if I used 22mm plastic to connect the WM to the waste outlet? (Using tees to provide rodding points for the future.)

It appears simple enough to me, yet I have this nasty feeling that I might have miscalculated somewhere! What have I overlooked?

Terry

[Phil L]

Why not just take the waste from the washing machine through the floor void and through the exterior brickwork, preferably near a drain?

This is never going to work, you are creating a trap which will hold 3.5m of waste water each time the machine finishes a load, the next time it starts to pump out, it has to shift that bulk of water before any new waste can escape - it's not going to happen.

This isn't a site, it's part of usenet, accesible through any newsreader like outlook express

The washing machine pump isn't strong enough to send water uphill, *after* it's shifted it 3.5m horizontally...and I can't see why anyone would want to when there are several other, easier ways of getting the water from the machine to the drain, if you utilise the underfloor void.

[Terry]

That is a possibility but I don't like the idea of discharging into the surface drain (even if it's what the neighbours do!)

The soil stack is cast iron and in a tight corner behind the sink unit (so no chance of getting to the outside wall at that precise point) and disappears into concrete (and I've no idea where it goes from there - I'm just glad I've never needed to find out!) so I don't fancy my chances of getting into the bottom of the stack.

Apologies for the error!

This is obviously the bit that's really confusing me. To my mind, as water will find its own level, the weight of water in the downhill bit will be slightly larger than the uphill bit and cancels out so that the pump won't actually be responsible for lifting the water at the other end

As I said above, I really wanted to avoid using the surface drain (although all the surrounding houses have been doing so for 102 years!)

Terry

[David Hansen]

On 7 Jan 2007 09:29:04 -0800 someone who may be "Terry" wrote this:-

Why not? Provided it is done properly, under the grid or via a back inlet gully, there should be no problems. I take it that there is a suitable gully.

If there was no resistance in the pipe this would be correct. However, especially in small pipes, there is plenty of resistance to the flow of water. Unless the pump and pipework are specially designed for the application then even if it does work that is likely to only be for a short time before something expires. What expires is likely to be the pump, or a joint.

[Phil L]

and almost all new houses for the past 30 years

So what is going to lift the water at the drain end if not the pump?

Why do you want to avoid what is a common practice all over the UK? - it's soapy water not industrial toxic waste!

[Roger Mills]

What do you mean by 'surface drain'? If you mean a gulley at surface level which connects to the foul sewer - or to a combined foul/storm sewer - there's no problem. However, if you have separate foul and storm sewers, and you're talking about discharging the washing machine output into the storm (surface water) drain, then *don't*. It is both illegal and antisocial - and will result in untreated chemicals (albeit diluted) being dumped straight into a river rather than being taken to the sewage works.

The washing machine pump is designed to lift the water enough for it it run into the top of a *vented* stack pipe - right next to the machine - and it needs to be able to find its own way out by *gravity* thereafter. A pipe, with a suitable fall, running under the floor would be fine. If you try to lift it again the other end, it will only flow at the rate at which gravity will take it - based on the difference in heights at the two ends. If you pump water out of the machine faster than this, the stack pipe will overflow. If you seal up the end of the stack pipe rather than leaving it vented, you'll almost certainly generate too much back pressure for the pump to cope with.

If the drains were installed over 100 years ago, there's a strong possibility that you have a combined foul/storm sewer - in which case, it will *all* go to the sewage works, and there's no problem with discharging your washing machine into it.

[Terry]

No, there is not a suitable gully as far as I know!

The description below is, I'm afraid, somewhat convoluted. I hope it will suffice.

The property is terraced, circa 1904, with a rear extension.

The present kitchen is at the rear of the main building, in front of the rear extension, which is 20cm lower. Behind the present sink unit, in the extension, is where the original kitchen was when the house was built. Behind that is what was the original outside WC. Both of the latter solid have concrete floors (all others being suspended.)

The soil stack, as I have said, is at the junction of the main building and the extension.

The surface water drain is by the far end of the concrete floor, just beyond the WC.

The original outside toilet was turned round at some point (before we occupied the property). The external waste re-arrangements for this are covered by some extremely hard concrete and there is no visible means of access! (I attempted to break through the concrete with a pick-axe some years ago - it just bounced off! When a friend pointed out that, just by trying, I could fracture pipework below that I couldn't reach, I gave up!)

In this area there is no rear access and there are no signs of access points anywhere in the back garden. I assume that both surface drainage and sewage pipes run under the house to the street at the front. The only access to anything below ground is to the stopcock on the rising main (in the front garden ~ 90cm from the property boundary) - apart from that: nothing! [I can see no access chambers on the adjoining property, either.]

I could run through the floor void to the rear wall and exit there, which would be above the level of the rear extention (and external concreted area) but the only way to reach the surface drain (15cm x 15 cm - at a guess) would be above ground (round the soilstack and along the wall.)

I understood that it is now illegal to discharge soapy/detergent polluted water into surface drains. Have I been misinformed?

[Terry]

I understood that it is now illegal to discharge soapy/detergent polluted water into surface drains. Also SWMBO who is fed up with lugging the WM across the kitchen, etc., and wants the thing plumbed in, is particularly concerned with these issues (so I'm trying to put out one fire without starting another!)

Terry

[Terry]

It seemed to make sense to me but I defer to your superior knowledge! Oh! If only it had been Volts, Amps and Ohms, I'm sure I could've worked it out for myself!

Terry

[Phil L]

Yes.

New houses have two seperate systems, one that goes into the sewers and one that goes into a river. Yours won't have this unless it is less than 20 years old and considering you've mentioned that it's over 100 years old, your drains take everything directly into the sewers, rainwater, soil, bathwater, sink, washing machine and eveything else....in other words, it will be going down the same drain pipes it has always gone down during your 'dragging across the kitchen' decades, along with surface water and roof water etc.

[David Hansen]

On 7 Jan 2007 15:24:25 -0800 someone who may be "Terry" wrote this:-

A manometer, which is what you would create, does not contain a large volume of water moving at speed through it. As a result the resistance to the flow of water is low and it will find its own level.

However, if one tries to push a large volume of water at speed through the manometer then the only way to do so is to overcome the higher resistance involved in doing this, with a large pump. The pumps in washing machines are not designed to do this and is likely to fail, even if it works for a while. During the time the pump is working it will be developing high pressures to force the water through the manometer, which makes it more likely that a joint will fail.

Even if the resistance is lowered by using smooth walled tube and large radius bends, rather than the hose usually used for washing machine outlets I doubt if washing machine pumps are designed for it.

Then there is the question of what happens when the pump empties all the water it can. There is now a slug of water moving along the pipe at considerable speed with no possibility of air getting past it. Get the design wrong and the pipe may be crushed.

[Terry]

As I've explained elsewhere in this thead (and probably done so in a very confusing way - so I won't attempt a repeat performance!) I have no clues whatsoever as to the sewer arrangements here...

This is the reason for my initial concern, backed up by SWMBO!

I think I'm starting to understand where my theory falls down now ...!

Thanks, Roger, you could well be right about this. As built, all waste water (kitchen, bath, etc.,) went into the storm sewer from all the properties around here. (Part of the mass building expansion from London eastwards into Essex around the turn of the 20th century.)

We're in Seven Kings (Ilford, Essex) and water from Fairlop Plain (to the north) drains to the south, via Loxford Water, into the lake in Barking Park and then, via the Roding, into the Thames. Slightly to the west, a similar process happens via the Cran Brook and the lake in Valentine's Park. Over the past few years, both waterways have become extremely polluted from newer estates to the north. For the best part of a century before, there was no problem, so it's a fair assumption that we've got a combined foul/storm sewer.

Terry

[David Hansen]

On 7 Jan 2007 15:17:59 -0800 someone who may be "Terry" wrote this:-

Perhaps you are at cross purposes with others in terminology. As others have said as the property is 100 years old it is very unlikely to have surface drains. Rather it will almost certainly have a combined drainage system; which takes water from toilets, washing machines, roofs and so on and puts it all in one drain. A gully does not mean the house has surface drains, even though surface water may go into the gully. Indeed a gully is a good indication of a combined drainage system.

Ask the Building Control department of your council what sort of drainage you have, they should be able to tell you.

[Terry]

Thanks for enlightening me, Phil. I'm sure SWHBO will be happier and grateful too! I suppose I'll just have to on with it, now!

Terry

[Terry]

detailed explanation - I think I've got it know - fortunately I'd read about manometers on this group a few weeks ago!

Terry

[Roger Mills]

I agree that a 100 year-old house will almost certainly have a combined drainage system.

But it is wrong to say that only properties less than 20 years old have separate systems. I don't know when the practice started, but my house is nearly 40 years old - and we have separate systems.

[Pete C]

This assumes there is no air in the pipe, which won't be the case at least initially.

I'd expect it will work if the hose leaves the machine near the base and goes down, then across the floor and up to the connection to the sink waste.

Basically down, along then up, NOT up, down, along, up.

If you do the latter, with air in the pipe there is a chance the two 'up' bits will combine and the pump will not overcome the additional head.

You'd then need a non return valve at the sink end, plumbing out kits include them. Once the machine has pumped out, it would help to hold water in the pipe and stop it flowing back then forward as the machine stops pumping and fills for the next wash/rinse.

I very much doubt the length of the pipe would cause a problem, but use an extended washing machine hose or 32mm waste, NOT 22mm pipe.

You could do a mock up with a washing machine pump from Ebay, local spares place, local tip etc. Get one that's self contained though and doesn't fit into a housing.

Also try asking on the forum at ukwhitegoods.

cheers, Pete.

[Phil L]

Ah but I'm up North, we've only just got electrickery and running water ! :-p

[Andrew Gabriel]

I've done this using 22mm solvent weld overflow pipe, and it works fine on both a washing machine and a dishwasher. I routed the pipe under the kitchen units, and it pops up in the sink unit where it rises to the required height and has an air break.

With a 32mm pipe, you'll end up with a much larger volume of water in the "trap" some of which will run back when the pump stops, and the water velocity will be much slower, which could result in debris settling out in the pipe over time. 22mm (or

21.5mm) solvent weld overflow pipework works just fine for this. An extended washing machine hose will offer much more flow resistance.

[Pete C]

Yes, I meant 22mm push fit water pipe, because the pipe liners are a fair bit smaller than 22mm.

cheers, Pete.