Waterwaterwater

[wobs]

I'm currently planning a new bathroom, and am looking for which would be the best option for toilets, in terms of water usage.

I've read that standard dual-flush toilets are fine until they wear out, and the valve starts to fail, letting water pass through.

I've also seen the Interflush system which can be fitted to an existing syphon system.

Does anyone have any opinions on which would be best to go for in terms of reliability, water usage etc.

Also, does anyone know of a decent extractor fan that can be fitted above a bath that has a shower, in a large bathroom.

 

[Flyfisher]

I've considered this recently and have been thinking about the possibility of using rainwater. I know it depends on the state of the property and the plumbing, but it shouldn't be too difficult to connect the toilet cisterns to a completely separate cold water tank. Then, arrange for this tank to be filled with rainwater.

For the property I have in mind, the roof arrangements are such that some gutters are higher than the cold water tank, so gravity would do the work. I imagine in most cases though that the rainwater would need to be collected somewhere lower than the cold water tank, so a pump would be needed to periodically top up the tank from the collecting point. Mains water could also be plumbed to the tank in case of prolonged drought, but this might never be needed if the rainwater reservoir was large enough.

I've read that sewerage systems are generally designed, or at least accustomed, to 'normal' flush volumes and that reducing this can lead to increased blockage problems as there may not be sufficient water flow to, er, keep things moving.

When you think about it, only a tiny proportion of the water we consume needs to be truly potable. Perhaps this sort of scheme could be extended to showers, baths, washing machines etc? In fact, thinking about it, many plumbing systems seem to run everything from the cold water tank except for the direct mains kitchen tap - so if you can remember to only drink/cook from that tap (which is pretty much the norm anyway), what would be the problem in topping up the existing cold water tank directly from a rainwater store? It would minimise the plumbing needed and could save a small fortune if you're on a water meter.

Am I missing something here?
(probably :? )

 

[Matey Plumber]

If you go for the rainwater option (grey water) for flushing make sure that you have a back-up supply for summer or busy times. Relying on rainwater alone would be dubious in summer too.
We have a building elsewhere on Campus where the system for going to clean water for flushing from grey water doesn't always work .....

It's an excellent idea though and should be adopted more widely.

 

[Jane Smith]

Grey water systems are those in which bath water etc is recycled, and less than 5% of these systems are still in use at 3 years old. Rainwater harvesting is much more successful, and you don't have to use chemicals to keep the water fresh.

Rainwater can be used--we put in a system this summer, to take the strain off our well. You need a filter between the downpipes and the tank, and have to size the tank correctly to make sure it isn't too small or too big--too big and the water sits around and goes stagnant. Google for "rainwater harvesting", there's a lot of info out there. We got it in for under £1,500 but did it all ourselves, if you buy a system off the shelf you'll pay a lot more.

 

[Flyfisher]

Very interesting; thanks for that. £1500 sounds pretty reasonable and should have a fairly short payback time if you were saving metered water.

Do you pump the collected, filtered rainwater directly up to the cold water tank? If not, how do you actually get it into your plumbing system? I take your point about the risk of stagnation - any tips for sizing the rainwater storage tank? I guess there must be some sort of calculator out there based around average rainfall, roof area and house occupancy. Interesting stuff.

 

[Jane Smith]

You mustn't mix the rainwater with mains water (or with well water either), I think it's against some BR rule. We have a set of tanks in the attic which loos and washing machine take water from: all other things take water pumped directly from the well, via a filtration system. The well-water top-up for the rain tanks has a valve on it to stop water from the tanks being sucked back accidentally, and so sending rain water to the well, which could cause contamination.

Find The Green Shop (somewhere near Gloucestershire I think) as it has a rainwater business and used to have all sizing information online. If you can't find their site, though, there are lots of others out there. They sell WISY filters but we got a different one as WISYs don't work properly if not 100% level, and if you're burying it it's difficult to ensure that it remains level once buried. Will try to find out where the filter came from and post a link. Can I post photos to this board? If so I do have a few of our filter in place. Beautiful thing it is too.