So...I'm about to do Rainwater Harvesting

[Pocster]

I originally was going down the route of rwh .

Even got a non return valve put in at the request of Bristol water .

Guy came out and actually told me it probably wasn’t worth it ; his reasoning :

 

maintenance / replacement pump

 

suggested not using it for toilets as can stain ( so some chemical agent needed adding to the stored water )

 

So use for what ? Watering the garden ? - that’s about it .

 

With the purchase costs of a tank etc I just couldn’t get any sensible roi .

So dropped the idea . As our water is metered it is relatively expensive , but even if I did install and used for garden , toilets , washing machine - I think savings would be minimal.

[Nickfromwales]

53 minutes ago, Pocster said:

I originally was going down the route of rwh .

Even got a non return valve put in at the request of Bristol water .

Guy came out and actually told me it probably wasn’t worth it ; his reasoning :

 

maintenance / replacement pump

 

suggested not using it for toilets as can stain ( so some chemical agent needed adding to the stored water )

 

So use for what ? Watering the garden ? - that’s about it .

 

With the purchase costs of a tank etc I just couldn’t get any sensible roi .

So dropped the idea . As our water is metered it is relatively expensive , but even if I did install and used for garden , toilets , washing machine - I think savings would be minimal.

Yup. Spend the money on something that has no moving parts, near zero maintenance, and gives an instant RoI. 
 

Solar PV, or more solar PV, or a battery.

[Pocster]

2 minutes ago, Nickfromwales said:

Yup. Spend the money on something that has no moving parts, near zero maintenance, and gives an instant RoI. 
 

Solar PV, or more solar PV, or a battery.

I did Uncle Nick.! PV, battery, then more PV and another battery.

With my EV ( admittedly low annual mileage ) my ROI is around 6 years from when first installed. If we have a stellar sunny summer I reckon I won't be far off break even this year.

[Nickfromwales]

54 minutes ago, Pocster said:

I did Uncle Nick.! PV, battery, then more PV and another battery.

With my EV ( admittedly low annual mileage ) my ROI is around 6 years from when first installed. If we have a stellar sunny summer I reckon I won't be far off break even this year.

Good girl. Help yourself to a cookie. 

[Pocster]

Just now, Nickfromwales said:

Good girl. Help yourself to a cookie. 

You've said that before haven't you?

[Temp]

We have an underground rainwater harvesting tank with a leaf filter on the input. It's been in use since 2007 and has accumulated about 1 ft of sludge in the bottom. 

 

We only use it for gardening and car washing but the water does have a brown tint to it. 

[Pocster]

28 minutes ago, Temp said:

We have an underground rainwater harvesting tank with a leaf filter on the input. It's been in use since 2007 and has accumulated about 1 ft of sludge in the bottom. 

 

We only use it for gardening and car washing but the water does have a brown tint to it. 

Out of interest are you going to ( able to ! ) get in there and suck the sludge out ?

[saveasteading]

40 minutes ago, Temp said:

about 1 ft of sludge in the bottom. 

That seems an awful lot, after a leaf filter. 

My 1920s brick single chamber  cess tank had that much on the bottom. Not bits of leaves.

Any idea what it is? would you change anything another time?

[Nickfromwales]

2 hours ago, Pocster said:

You've said that before haven't you?

Yes. I'm sorry.

 

 

 

 

There are no cookies. "somebody" ate them.

[Temp]

On 27/01/2025 at 14:14, Pocster said:

Out of interest are you going to ( able to ! ) get in there and suck the sludge out ?

 

Yes. There is a manhole big enough to climb in but that might be dangerous (lack of oxygen or too much CO2 etc).

 

I can see me hiring a cespit company to pump it out at some point.

 

 

[Alan Ambrose]

Sounds like a silt chamber is a really useufl addition to RWH.

[Temp]

On 27/01/2025 at 14:28, saveasteading said:

That seems an awful lot, after a leaf filter. 

My 1920s brick single chamber  cess tank had that much on the bottom. Not bits of leaves.

Any idea what it is? would you change anything another time?

 

We have a lot of trees and I think some leaf fall rots in the gutters before being washed through the leaf trap when there is a heavy downpour. I have to vacuum out the gutters twice a year with a wet vac but it's impossible to get all the "compost" out of them.

 

 

[Stu789]

I'm considering rainwater harvesting and thinking that a gutter outlet spider + downpipe leaf filter + silt trap + deeper tank so pump draws from higher up the tank more of the time is going to give the best chance of cleaner water - if the downpipe leaf filter is good enough then maybe delete the spider.   Really interested how clean the water is for an installation where someone has taken these steps - brown muddy water in the toilets and washing machine will be a tough sell to my other half!

 

Also clear that financial considerations are very much secondary - assisting site water management & being environmentally responsible being my drivers.  

[Gone West]

56 minutes ago, Stu789 said:

Really interested how clean the water is for an installation where someone has taken these steps

My Victorian underground rainwater tank only had a two stage sand filter bed and the water was crystal clear in the tank. The pump drew the water from around 300mm off the bottom of the tank.

[ToughButterCup]

On 28/01/2025 at 14:46, Alan Ambrose said:

Sounds like a silt chamber is a really useufl addition to RWH.

 

That is exactly what it is @Alan Ambrose

 

@Temp needs to add a settlement tank to his set up with a 3 foot sump at the bottom of it so he can use a standard 2" pump to get rid of the sludge - once very few years. And have an overflow into the operational tank of course...... in effect, a skimmer.

Sorry @Temp, talking about   you .....didn't see you standing there 😑

[SteamyTea]

Seems to me that it is the filtration/treatment of RWH that is the problem.

It should be possible to design a self cleaning vortex filter for the input and then a regular water treatment filtration and sterilisation system for the output.

[ToughButterCup]

14 hours ago, SteamyTea said:

Seems to me that it is the filtration/treatment of RWH that is the problem.

It should be possible to design a self cleaning vortex filter for the input and then a regular water treatment filtration and sterilisation system for the output.

 

...  And hence the expense, which makes it unviable.

Settlement, however only needs expenditure once - a second tank(let) which needs cleaning every once in a while. And a chlorine ( Chlorox ?)  tablet once in a while,  dropped into the settlement tank.

[SteamyTea]

25 minutes ago, ToughButterCup said:

And hence the expense, which makes it unviable.

That is probably because not many are made, and none of them are for RWH as they are usually modified swimming pool filters.

[Simon R]

On 29/01/2025 at 15:29, Stu789 said:

 Really interested how clean the water is for an installation where someone has taken these steps - brown muddy water in the toilets and washing machine will be a tough sell to my other half!

Our rain water is still clear after 3 years use and is used for washing machine , toilets, window cleaning and garden watering. RWH was not on our original build plan, but a 19K quote to connect to surface water drainage made it a sensible option. After minimal research a Kingspan Klagster 4,600ltr system was purchased. The system included pump and controls for monitoring and maintaining the system. It got delivered and  installed early in the build cycle, when we came to use it for the first time two years later the pump had failed. The Kingspan guarantee was  1 year from delivery and they wanted £300 just to look at the pump. Not impressed. To cut a long story short a call to Anglian pumps and some very good customer service the pump was replace with a Divertron pump. The pump is stainless steel  and has a float intake, so it's always taking from the top surface of the the water. The pump also auto senses when an outlet is opened. Having ditched the complex Kingspan control system it's been running for three years without problem.

I think having a good leaf filter and float intake are key factors in keeping the water clear. We're also fortunate that we don't get much debris in our gutters so silt build up is not a problem. Being able to clean our windows with a pole has been and unexpected bonus, not something you can do with tap water.

With the benefit of hindsight I'd have bought a good tank with leaf filter and a decent pump, keep it simple, forget the fancy control system.

 

[saveasteading]

I may have said this already.

 

I would not put one in to a new house.

I might well for an office or some industrial uses.

This is down to the cost of the tank plus the completely separate plumbing to wc's and outside taps.

ie an office has lots of flushes in the day. A big office can justify the capital and maintenance. So would any business with vehicle washing.

 

I do plan though to put a big tank in- line in the garden.  Maybe 3m3. This will be for garden watering only, by hand or electric pump, tbc.

 

I put one in to an office and it served about 40 persons. In theory 5m3 was the size but we put in 10m3 to catch all of any storm in summer from a 500m2 roof. The water bill was £80 p/a due to being for kitchen and whb use only. Say £150 at current prices.

It never ran out.

The pump failed twice in 6 years use, and slso allow for electric use.

The 2 stage sump had a tiny coat of silt on the bottom. 

Sewage bills were tiny too, being based on mains water used.

 

Payback was projected as 6 to 8 years but was 3, maybe 5 allowing for power.