Rainwater harvesting

[Thorfun]

1 minute ago, PeterW said:

 

ACO or linear drains at ground level - especially where vehicles are present such as driveways and garages - can introduce hydrocarbon contamination into the rainwater tanks

ok, so if they're not near the driveway or garage it would be ok to drain to the RWH tank? our one is at the back of the house by the door leading to the patio

[PeterW]

If you can divert it to the soakaway it is better - stops anyone pouring buckets with rubbish/dirty water/chemicals down the channel. Also worth adding closed gullies to all of your downpipes

[Thorfun]

1 minute ago, PeterW said:

If you can divert it to the soakaway it is better - stops anyone pouring buckets with rubbish/dirty water/chemicals down the channel. Also worth adding closed gullies to all of your downpipes

ahh, yes. the 'pour buckets of bleach in to the drains' scenario. hadn't thought of that! 

 

thank you so much. I'm glad I read these threads and will go back to the civil engineers with the request that all ACOs go direct to the water course.

[Bitpipe]

Yep, @PeterW explained it well.

 

Garage ACOs drain direct to soak as does overflow of the RWH tank.  House and garage roofs drain to RHW inlet. 

 

As we have the basement as a full footprint, there is no need for drainage around the house as it's one giant French drain. Land drain at external perimeter of basement which also goes to soakaway.

[Thorfun]

got another question about RWH and thought I'd keep it here rather than start a new thread.

 

Direct vs Gravity? 

 

I can see pros and cons for both, here's a basic list that I can think of although I've probably missed some obvious ones.

 

Direct fed Pros:

1. no header tank

2. cheaper

3. reduced risk of Legionalla

4. reduced plumbing complexity needing to run extra pipework to a tank in the loft

 

Direct fed Cons:

1. pump runs every time a toilet is flushed

2. slow drip leak from a toilet will cause the pump to keep cycling to compensate for that small leak

3. a low RWH tank level will result in mains water filling the RWH tank rather than a header tank in a gravity system (at least I assume that's how it works)

 

I guess the Gravity fed Pros and Cons are pretty much the opposite of the direct fed ones.

 

Now, I know on here folk don't seem to think that RWH doesn't make sense financially but we really like the concept and reducing our reliability on the main utilities where possible. we also think that we can incorporate the cost into the total build budget.

 

so with that in mind, would you go direct or gravity fed RWH and why?

[PeterW]

@Thorfun how many toilets are you planning on supplying and how big is the rainwater tank ..?

I wouldn’t have a header tank as I can’t see the point in storing water in an attic, and unless you’re in the middle of nowhere then mains water failures are few and far between. 

 

[Thorfun]

8 minutes ago, PeterW said:

@Thorfun how many toilets are you planning on supplying and how big is the rainwater tank ..?

I wouldn’t have a header tank as I can’t see the point in storing water in an attic, and unless you’re in the middle of nowhere then mains water failures are few and far between. 

 

 

I've been recommended a 4500 - 5000 litre tank when taking in our roof size and average rainfall. we will have 6 toilets in the house (obviously not all of them will be used at once!) with a regular occupancy of 4 humans (the dog and cats don't often drink from the toilets so that will save us some water).

 

will also be used for washing the car, watering the veggies etc and thinking of potentially using it for the washing machine but will need to do more research on the potential pitfalls of that one.

 

thanks for your opinion on not needing a header tank. I'm leaning that way, especially as it's about £500 extra for the gravity system and that's before the extra plumbing required. and for the money saved I could replace the pump later on down the line if required and still be quids in.

[PeterW]

On 16/05/2019 at 16:46, Bitpipe said:

So just sent it back to Amazon and I've ordered a 1100W equivalent for £39.

 

Hoping that does a better job.

 

out of interest did that work ..? Have you got a link ..? And how big is it as I may need to install one. 

[Thorfun]

ps. was told that the RWH tank needs to overflow occasionally to 'wash away' any pollen that could cause a sulphurous smell that has gotten through the filter.

[PeterW]

1 minute ago, Thorfun said:

ps. was told that the RWH tank needs to overflow occasionally to 'wash away' any pollen that could cause a sulphurous smell that has gotten through the filter.

I’ve basically got a single inlet / outlet that if it the tank is full then the water backs up and down the same tee to overflow. 

[Thorfun]

Just now, PeterW said:

I’ve basically got a single inlet / outlet that if it the tank is full then the water backs up and down the same tee to overflow. 

cool, so yours is sized so that it will overflow occasionally? 

[PeterW]

Only put in 2200 litres so yes - will overflow. Just replacing the pump as the surface pump has given up. 

[JamesP]

I fitted a direct feed.  Had ordered the gravity fed system but wanted to simply the installation so went with this : F-Line 5000 Litre Rain Backup in a Box System.

All the toilets and washing machine can be fed via the mains in the event of power cuts  / pump failure.

[Thorfun]

2 minutes ago, PeterW said:

Only put in 2200 litres so yes - will overflow. Just replacing the pump as the surface pump has given up. 

interesting. how long did the pump last?

[Thorfun]

4 minutes ago, JamesP said:

I fitted a direct feed.  Had ordered the gravity fed system but wanted to simply the installation so went with this : F-Line 5000 Litre Rain Backup in a Box System.

All the toilets and washing machine can be fed via the mains in the event of power cuts  / pump failure.

that's great to know @JamesP as I've been looking at those F-line systems (as well as the Rain Sava systems). how is the F-line system? you've gone for the same sizing I'd be looking at in the F-line series.

 

why did you choose the F-line over a.n.other system?

Edited September 1, 2020 by Thorfun

[PeterW]

13 minutes ago, Thorfun said:

interesting. how long did the pump last?

About a year but wasn’t new when it was fitted so not worried. 

[Thorfun]

Just now, PeterW said:

About a year but wasn’t new when it was fitted so not worried. 

ok. thanks. I was just trying to get a feel as to how long a pump 'should' last in a direct fed system. if it's every couple of years then a gravity fed system might make more financial sense in the long run as the extra cost will be mitigated by a less frequent pump replacement. but if the pump lasts for 10 or 15 years then 2 of them will probably outlive me!

[JamesP]

34 minutes ago, Thorfun said:

that's great to know @JamesP as I've been looking at those F-line systems (as well as the Rain Sava systems). how is the F-line system? you've gone for the same sizing I'd be looking at in the F-line series.

 

why did you choose the F-line over a.n.other system?

My brother fitted the same product except 7500L a few years back.  Shallow dig was a factor though to be honest I did not look at any other options. It just works.