Is Rainwater Harvesting worth it when borrowing

Troy McClure

I was quoted 2.5k for a rainwater harvesting system. I though with the water charges coming in it's worth looking at.
Allowing that without going big money the do toiltets and washing machine, only and also allowing it's mortgaged money that paying for it as it's a new build, is it worth it? Whats the payback?

I have been told people use them for showers, but as there is a very slim chance of something been in the water it's not recommended. Is this the same risk as if you were using well water for showers?

sinnerboy

This is the monthly cost of borrowing €2500 , for various interest rates over various periods of time.

So lest pluck €12.35 from it ( 1 year fixed @ 4.29% over 30 years ) would give an annual cost of €147.84 roughly. ( Don't forget your life insurance premium will be affected but let's omit this for now )

We don't know to what amount what water charges will be levied but I don't see €100 per year being too far out ( I'm basing this on radio/tv I've heard discussions only ) . So at current interest rates and at current guessing at water charges you can't really make an economic case.

However if we look at figure E-11 page E-7 here we see a state wide cost of €800m ( set to rise over the years ) and if we look here we see 1.287m homes in the state. If simply divided we get €621.00 per household. If you take out the can't-pay part of the population the result will rise.

Crystal Ball Time.
It's obvious that a water charge of the order of €100 per year would be political . It would be introduced initially "painlessly" . If €100 is then raised by 20% per year it will rise to over €200 in 4 years to over €400 after 8 years and almost €900 after 12 years. If this happens and if mortgage interest rates remain much the same in 12 years time then you could be looking at a water charge of €75 per month vs €12.35 part of the mortgage debt related to the rw harvesting installation.

However €2500 will buy you a tank in the ground with a pump for the garden lawn and flowers only. This gives you a typical breakdown of a persons domestic water use. 148 liters per day. My estimate to provide a separate tank in the house ( pumped from the harvesting tank ) which stores water for the toilets and washing machine only and with split plumbing to suit would be at least another €2k. At least the same again to install filters to make the harvested water safe for personal hygeine. I would never consider attempting to make it safe for drinking.

So I've left a lot of questions unanswered here. But I hope some scope for educated guessing.

.

Do-more

I don't know how typical it is of other European countries but here in Sweden we pay an average of €50 per month for water charges of which approx. €18 is a standing charge and the remainder is variable according to usage that's a house with 2 adults and 2 kids.

So sinnerboy's estimate of €600 per year is probably highly likely within a few years.

Troy McClure

Good breakdown thanks. I have asked a couple of people. Some say it will be a fixed fee as it will cost too much to install meters. I think it's in the IMF deal though correct me if I am wrong on that.

So do you think it's worth doing? I am also tinkering with the idea of plumbing for it and maybe putting in a tank in the ground as part of the ground works. I could put in a pump and filtration system down the road

Do-more

Troy McClure wrote: »

Good breakdown thanks. I have asked a couple of people. Some say it will be a fixed fee as it will cost too much to install meters. I think it's in the IMF deal though correct me if I am wrong on that.

So do you think it's worth doing? I am also tinkering with the idea of plumbing for it and maybe putting in a tank in the ground as part of the ground works. I could put in a pump and filtration system down the road

It's really only for you to decide, as there are no solid figures available yet on what water charges are going to be no one can give a definitive answer.

Plumbing a separate circuit to feed toilets etc. that could use harvested water would seem like a sensible step as even if you don't do anything else it will give you the flexibility to retro-fit in the future without doing any re-plumbing within the house and the additional cost at this stage should be low.

After that it's all really all finger in the air stuff.

gman2k

A buddy of mine who was living in the UK was getting water charges of £110 per MONTH.
As the new Irish Water entity will soon be privatised, and probably then owned by one of the UK utilities, expect big bills within 10 years.
I would strongly encourage the OP to go for it. Really impossible to fully retrofit efficiently.

Troy McClure

gman2k wrote: »

.
I would strongly encourage the OP to go for it. Really impossible to fully retrofit efficiently.

Why do you think this? If the plumbing on the inside is done for it then all the work is outside later on. Buy and concrete tank and stick it in the ground with this and I would have thought it's pretty future proofed no?

gman2k

Troy McClure wrote: »

Why do you think this? If the plumbing on the inside is done for it then all the work is outside later on. Buy and concrete tank and stick it in the ground with this and I would have thought it's pretty future proofed no?

What you've described there is not really retrofit!

For Rain Water Harvesting, if you wanted to use the RW for 'Grey' water purposes only, then you need a direct feed from the rain water storage tank, possibly to a secondary Attic based cistern, and then feeds to your toilets etc.
This is the type of stuff that's very difficult to retrofit.
Also, when at build stage, there's not a huge amount of additional work involved to divert your RW runs to your conc. tank and then onto soakaways/ sewer etc. (You already have the machinery, labour, trenches etc on site)
Again, trying to do this work as a retrofit is messy and expensive.

Basically, IMO it's a good investment at build stage, not so cost effective at a later date.

BryanF

I'm aware of a gravity feed attic rainwater harvesting system that can be retro-fitted.