using rainwater in toilet cisterns

slipstream

hi,

MODs: i posted this in plumbing previously but thought it might be more relevant here?

the architect on our bungalow renovation has suggested using gravity fed filtered rainwater from the ~ 25sqm flat dormer roof for the toilet cisterns.

to do this, i guess we would need a separate cold water storage tank, rainwater header tank with overflow and perhaps a mains backup.

we would hope to connect toilet cisterns and perhaps the washing machine (if it was advisable) to this.

here is a list of the outstanding queries/issues i have -
1) What type of filters to use?
do these need to be replaced?
do they require maintenance? if so, how much maintenance is needed?
2) Would inlet/outlet pipes to/from the tank be insulated to reduce cold bridging (more of a construction than a plumbing concern)?
3) Would a water trap be needed on the inlet and outlet (to aid air tightness among other things)?
4) Where would the overflow go if the rainwater storage tank is full?
5) Would a mechanical or electrical mains backup for when the tank is empty be better?
6) I have heard concerns that a basic system could fill with bacteria (even moreso in a warm roof). What are peoples thoughts on this?
7) Would the rainwater would be suitable for use in washing machines?

do you guys have any experience or advice on setting this up?

slip

greasepalm

i looked at one briefly at a show as they had narrow butts and had pumps to pump water out,based in -snip- i think as there was/is -snip- there to see it in use.unsure of their name

-snip-

shane ryan 2013

slipstream wrote: »

hi,

MODs: i posted this in plumbing previously but thought it might be more relevant here?

the architect on our bungalow renovation has suggested using gravity fed filtered rainwater from the ~ 25sqm flat dormer roof for the toilet cisterns.

to do this, i guess we would need a separate cold water storage tank, rainwater header tank with overflow and perhaps a mains backup.

we would hope to connect toilet cisterns and perhaps the washing machine (if it was advisable) to this.

here is a list of the outstanding queries/issues i have -
1) What type of filters to use?
do these need to be replaced?
do they require maintenance? if so, how much maintenance is needed?
2) Would inlet/outlet pipes to/from the tank be insulated to reduce cold bridging (more of a construction than a plumbing concern)?
3) Would a water trap be needed on the inlet and outlet (to aid air tightness among other things)?
4) Where would the overflow go if the rainwater storage tank is full?
5) Would a mechanical or electrical mains backup for when the tank is empty be better?
6) I have heard concerns that a basic system could fill with bacteria (even moreso in a warm roof). What are peoples thoughts on this?
7) Would the rainwater would be suitable for use in washing machines?

do you guys have any experience or advice on setting this up?

slip

Hi
Electric backup
Rainwater excess goes down the storm drain
Bacteria will need filters sediment filters carbon filters etc
Cold bridging is for thermal imaging cameras
Water traps are toilets and basins etc
Installing a basic system is pointless .

you need to install the correct system for your personal needs on usage depending on the size of your roof catchment area .

Doing it diy is possible but if you pay with bananas you lol get a monkey

North West

Hi slipstream
25 sq m area will not give you enough water for what you propose. You need to consider what exactly you want to do and take it from there. A toilet cistern will use 9 lts of water per flush. A person will flush a toilet at least 5 times a day, which would use 45 ltrs of water alone, A washing machine approx 60 Ltrs per wash, a modern dishwasher will use 45 Ltrs per wash. Just to give you an idea of water use.
can you catch more water off your roofs?
How many wc;s in house ?
How many people in house ?
Do you intend to put a rainwater tank above of below ground ?
What exactly do you wish to do with water ie toilets, washing machine, dish washer. garden watering, car washing etc.?
You will have to consider all these things and then look at a system that would suit your purposes. It;s not as simple as you think,
NW

bluesteel

Serious question - have you considered using a urinal to save water? Some of them have covers etc and are less unsightly?

Curious Geroge

slipstream wrote: »

hi,

MODs: i posted this in plumbing previously but thought it might be more relevant here?

the architect on our bungalow renovation has suggested using gravity fed filtered rainwater from the ~ 25sqm flat dormer roof for the toilet cisterns.

to do this, i guess we would need a separate cold water storage tank, rainwater header tank with overflow and perhaps a mains backup.

we would hope to connect toilet cisterns and perhaps the washing machine (if it was advisable) to this.

here is a list of the outstanding queries/issues i have -
1) What type of filters to use?
do these need to be replaced?
do they require maintenance? if so, how much maintenance is needed?
2) Would inlet/outlet pipes to/from the tank be insulated to reduce cold bridging (more of a construction than a plumbing concern)?
3) Would a water trap be needed on the inlet and outlet (to aid air tightness among other things)?
4) Where would the overflow go if the rainwater storage tank is full?
5) Would a mechanical or electrical mains backup for when the tank is empty be better?
6) I have heard concerns that a basic system could fill with bacteria (even moreso in a warm roof). What are peoples thoughts on this?
7) Would the rainwater would be suitable for use in washing machines?

do you guys have any experience or advice on setting this up?

slip

I talked a similar thing over with my eng and plumber and there is zero return and alot of heartache in getting it done so we left it. You might see that the same money put into drilling your own well would be better spent.

shane6977

bluesteel wrote: »

Serious question - have you considered using a urinal to save water? Some of them have covers etc and are less unsightly?

Or just pee in the sink!

Sorry...joking...couldn't resist!

Grey_Goose

slipstream wrote: »

hi,

MODs: i posted this in plumbing previously but thought it might be more relevant here?

the architect on our bungalow renovation has suggested using gravity fed filtered rainwater from the ~ 25sqm flat dormer roof for the toilet cisterns.

to do this, i guess we would need a separate cold water storage tank, rainwater header tank with overflow and perhaps a mains backup.

we would hope to connect toilet cisterns and perhaps the washing machine (if it was advisable) to this.

here is a list of the outstanding queries/issues i have -
1) What type of filters to use?
do these need to be replaced?
do they require maintenance? if so, how much maintenance is needed?
2) Would inlet/outlet pipes to/from the tank be insulated to reduce cold bridging (more of a construction than a plumbing concern)?
3) Would a water trap be needed on the inlet and outlet (to aid air tightness among other things)?
4) Where would the overflow go if the rainwater storage tank is full?
5) Would a mechanical or electrical mains backup for when the tank is empty be better?
6) I have heard concerns that a basic system could fill with bacteria (even moreso in a warm roof). What are peoples thoughts on this?
7) Would the rainwater would be suitable for use in washing machines?

do you guys have any experience or advice on setting this up?

slip

Well back in the late 70's early 80's I was one of a family of 8. I had a tank built with concrete blocks and plastered on the inside - used a cement sealer in the plaster - I think it was called pudlo. This tank held 1,000 Galls. It was filled from the roof of an old type bungalow and a small roof extension. A pipe was sealed into the bottom of this tank with a wire mesh filter on the end in the tank which in turn connected to a mini pump inside in the house (in this case located in the hot press) A pipe from the pump was connected to a tank in the attic. This attic tank served hot/cold water to kitchen sink, one toilet cistern, one W.H. basin and one Bath. 90% of the time this system kept all systems running. The tank in the attic had a switch connected to the ballcock which turned the mini pump on and off when the water level in the tank reached a certain level on the way down and vice versa on the way up. The overflow from the tank outside went with the storm water. This system kept all the systems running for at least 10/years until it was changed over when the treated mains water came along. This was a simple system that does work and if I were to have a similar system today, I have a feeling all I would have is a bigger tank outside to cope with the extra utilities. Of course I would also consider having easy access to the Irish Water water or treated water to use as a top up in case of a drought; and for drinking.

canboy

Grey_Goose wrote: »

Well back in the late 70's early 80's I was one of a family of 8. I had a tank built with concrete blocks and plastered on the inside - used a cement sealer in the plaster - I think it was called pudlo. This tank held 1,000 Galls. It was filled from the roof of an old type bungalow and a small roof extension. A pipe was sealed into the bottom of this tank with a wire mesh filter on the end in the tank which in turn connected to a mini pump inside in the house (in this case located in the hot press) A pipe from the pump was connected to a tank in the attic. This attic tank served hot/cold water to kitchen sink, one toilet cistern, one W.H. basin and one Bath. 90% of the time this system kept all systems running. The tank in the attic had a switch connected to the ballcock which turned the mini pump on and off when the water level in the tank reached a certain level on the way down and vice versa on the way up. The overflow from the tank outside went with the storm water. This system kept all the systems running for at least 10/years until it was changed over when the treated mains water came along. This was a simple system that does work and if I were to have a similar system today, I have a feeling all I would have is a bigger tank outside to cope with the extra utilities. Of course I would also consider having easy access to the Irish Water water or treated water to use as a top up in case of a drought; and for drinking.

When our council cottage was built in the 80's we had a similar system and it worked out fine. I am considering doing something similar again now with a smaller container taking rainwater from the roof and pumping it directly into the header tank in the attic. Just trying to decide which type of pump to get. I think a submersible pump should work, as I would only be sending up water a couple of times each week and the mains will still be an option.

Grey_Goose

canboy wrote: »

When our council cottage was built in the 80's we had a similar system and it worked out fine. I am considering doing something similar again now with a smaller container taking rainwater from the roof and pumping it directly into the header tank in the attic. Just trying to decide which type of pump to get. I think a submersible pump should work, as I would only be sending up water a couple of times each week and the mains will still be an option.

Hello canboy

I am not a great authority on plumbing. I am thinking some of people will debate with themselves that if they are considering an alternative system of water to run cisterns and maybe shower/bath.
Of course this will depend on the demand the household will have (number living in etc).

I feel just to be on the right side the advice of a plumber would be the best option. I am just thinking aloud here:- Have you considered pumping the rainwater from your new outside tank to a separate tank in attic. If your outside tank is running low from a draught you would have the option of topping it up with the mains water. This type of system would run all utilities.

For drinking water making tea etc just connect direct to the Kitchen Sink. One could go on and on but I think you get the picture.

I hear in my neighbourhood talk about submersible pumps and I would be confident this system would also work for you. I don't know if the mini pump I talked about earlier is still on the market. It would be best to do some research on this to work out the best option for pumping a short distance.

I would feel though that if one is considering an alternative rainwater system that it would be best to have this system as automated as possible. In this way you have continuous flow and avoid airlock.

Best of luck with whatever you decide and hope it will all work out to your satisfaction.

I am not a professional plumber and I would advise anyone considering an alternative system, if they are not confident in doing the work themselves. to get help from a professional.

canboy

Hi Grey_Goose,
thanks for your reply. I would be thinking of using the header tank in the attic, where I would tie up the ball-cock and top up with my rainwater every few days. Times when water is scarce (as if), or time does not permit, I just release the ball-cock and wait until the next time to top up.