Rainwater catchment

I am building a house with a reputable builder in Melbourne Western suburb.
We want to save water so we paid almost $900 for rainwater catchment system to our builder.
We got that price because it doesn't include water tank.
We assume that with that amount, the catchment system will connect to all the toilets.
But we are told that it is only for water catchment point.
What does rainwater catchment point mean and it is reasonable to cost that much for a catchment point?
Please discuss

I would say that a water catchment point is for the redirection of all the down pipes from the roof to a single point. $900 doesn't seem unreasonable, but it would depend on the size and layout of the house.

No point in connecting this point to the toilets.

Without storage (rainwater tank) the toilets would only be able to flush while it was raining.

Thank you. We didn't include the tank because we are thinking to install it ourselves in a later stage.
Well, it seems like we can only use rainwater for gardening and not for flushing the toilet then.
Thanks again.

You will need a tank, and a pump, before you can think about flushing the toilets

Was it a written quote and if so, is "rainwater catchment system" all it states? If not, what does it state?


A rainwater catchment point is a downpipe. What $900 is for is a mystery to me and you have been treated like a mushroom. You need to find out from the builder what they are supplying.

It is possible that the $900 has only gone towards fitting some pipes and a check valve that connects to the mains water pipe. The pipes would protrude through the outside wall and this would then dictate that you have a tank sited at that location and the pump would then supply a mains water switching device that is plumbed to the pipes ("rainwater catchment point") protruding from the wall that the builder's plumber has/will plumb.

People get ripped off badly with rainwater harvesting systems and nearly every photo that I have ever seen on Homeone of someone's new home rainwater harvesting system has shown a sub standard installation. If it is done properly, you could pay up to 50% less and have a quality system that delivers a greater amount of good quality water. What stage is your house at and has any plumbing already being done?

In the email, the contact person said we only ask to make provisions for a future rainwater tank. It said we didn't ask for plumbing rough in to the WCs in the home.
In the contract, it said, (3-270. Provides 100 mm PVC downpipes in lieu of standard for future rain water tank connection.

The brick work is halfway and plumbing is done, as well as wall plastering.

In SA, it sounds like a similar thing they call a "rainwater plumbing loop" and the owner has to get the rainwater tank themselves later. In some estates and suburbs we have a purple tap which is reclaimed water, and this can be substituted for the rainwater tank. The plumbing loop would go from the roof downpipes to the rainwater tank, and then back to 1 of the toilets by default. Like the others have said, You would need to add on a rainwater tank and pump.

Best thing is to check with your builder about what this means

We want it to connect to the toilet but the builder said it won't be connected to the toilet as it is only for rainwater catchment.
I thought every house has gutter and it's easy to put up a catchment point by ourselves if the catchment means adding a pipe to connect to the tank.
If that's the case then charging $880 is too much.
I have contacted the biuilder what they are supplying us with that $880 but so far no response yet.

Their description is disturbingly strange, you need to clarify it. Fitting 100mm pvc downpipes would cost little extra, I hope that you are not paying $900 just for 100mm pvc downpipes!!!

The usual course of events is to plumb what I described earlier and what MJT has called a "rainwater plumbing loop" for later connection from a mains switching device. The pipe it taps into will supply the cisterns.

Eliminating this usual plumbing method will save $$$ on the cost of a mains water switching device (usually an expensive Davey RainBank) and the cost of the parts and labour involved in plumbing the loop. You can eliminate this by plumbing in a separate PEX line to supply a separate (second) cistern valve on each cistern provided the cistern is compatible. The mains water and the rainwater lines will have their own (WC) wall isolation valves that serve as manual change over devices (one on, one off) in the event of the water tank emptying.



Cistern valves are also low flow end fixtures and so you don't want a powerful pump that will use heaps of energy and virtually dead head when supplying the cistern, considerably shortening the pump's life. Most people also get ripped off $$$ with the pump supplied.

If you also want to use the pump to water the garden, just fit a 25mm blue stripe poly pipe between the pump and the garden tap and buy an 18mm hose to considerably reduce friction loss.

You don't always need to have an overflow pipe plumbed to the tank either as there is a way to eliminate this. Another $$$ saving.

A note on supplying rainwater to cisterns. Years ago, cisterns were usually a single flush 12 litre capacity unit and these did use a lot of water but these days the cisterns are twin flush low volume units and water savings are best found elsewhere. Without doubt, a well set up rainwater harvesting system that delivers clean water to the pump will produce the biggest water savings these days when supplying a HWS. Even with a well set up system, it is still best to use a 10 micron filter. If one particular toilet is 'high use', then it is still worthwhile also connecting to it.

Unless the stormwater/roof drainage compliance required 100mm pvc downpipes, there was absolutely no need to fit them.

Thank you SaveH2O.

I asked what we are being supplied for the $880 we paid and this is the reply from the builder.
They say we are paying for building variation we made.

This is the exact reply.
(As per variation you are paying for 100mm diameter PVC downpipes in lieu of Colorbond plus an additional run for approximately 5 meters to a point of discharge that you will be able to connect your future tank to.

Regarding your toilets - as per your estate requirements we already made provisions for the recycle water to your toilets.
Provide connection of 1no additional toilet suite to class A recycle water system (3no toilet suite connection in total) = $154

Provide tapping and connection to class A recycle water system including the following;
-connection to 2No toilet suites
-water meter and garden tap to front yard
-additional garden tap to rear yard( located adjacent to the existing garden tap)
That's the reply.
And for that we are paying another $1419.

When we inspect the property we didn't see recycle system connected to the toilet. It suppose to be green pipe isn't it?

About $500 of the $880 will be the variation charge. Has the work being done? If not, then you should cancel it and save your money.


The Colorbond downpipes cost about 50% more than 100mm dwv pipe.

I have developed a rainwater harvesting system that would have allowed you to retain your Colorbond downpipes. It is unfortunate that you were unaware of it.

I am puzzled by the reference to the plural "100mm diameter PVC downpipes". Why would they change all of the downpipes?


This is to connect the water tank's overflow to the stormwater system. An overflow is necessary for standard rainwater harvesting systems but not necessary for all designs.


Recycled water pipe is lilac. There is a charge for the recycled water that you use and it is compulsory for the builder to connect it to the toilet.

Oh no. What a mess we are in. I have no idea that colorbond one is more expensive.
Thank you. The installation hasn't been done yet but it's in the contract so I'm not sure if I can cancel.
Thank you.

I don't understand. How can they be charging you a variation if it is in the contract?

All you are getting is cheaper 100mm downpipes which you don't need and (it would seem) an overflow return to stormwater which can also be done away with.

I assume that you would prefer your Colorbond downpipes.

If you decide that you still want a tank and if it was positioned next to the house, then one downpipe would drain directly to the tank and the tank's overflow would then connect to where that downpipe had joined the stormwater. With that usual situation, then why would they supply "an additional run for approximately 5 meters to a point of discharge that you will be able to connect your future tank to." It doesn't make sense unless the tank is going to be away from the house.

One diverted downpipe would not be enough but additional downpipes would either need to be buried and diverted to the tank where they would then rise out of the ground to the top of the tank or else be plumbed along the house wall...which is ugly.

For now, I would be asking them to explain just what the ""additional run for approximately 5 meters to a point of discharge" is.

If possible, I would also try to get this very vague clause removed and the monies involved deducted from the total.

If you want to install a rainwater harvesting system to perhaps supply a garden tap, then I can advise on the easiest, neatest and cheapest way to do it but because you will have re-cycled water connected to the toilets, the tank's utilisation would not be high outside of the summer months unfortunately...unless you were able to connect to the HWS.

I contacted my builder said we don't want PVC downpipes as it is cheaper than colorbond one.
And i told them, if all it does it getting a water catchment point for us then we don't want it to be installed.
I got the reply a few minutes ago saying that since we already asked for it and signed it, we must have it.
I will just go to consumer affairs.
Thanks

If you have a standard rainwater harvesting system, you will need pvc downpipes but there would usually only be a couple of downpipes affected.

Contracturally, they have you over a barrel. The big problem is that the wording is vague and you don't know what you are actually getting or if you even need what they intend doing. It should have been properly worded and explained to you.


The way I read the builder's discombobulated reply is...

1. You are almost certainly paying for a variation. This is usually a $500 charge. Ouch!!!

2. You are having all of your Colorbond downpipes replaced with cheaper PVC downpipes.

3. I can only assume that the "5 metres to a point of discharge that you will be able to connect your future tank to" is a connection to the stormwater from the proposed tank's overflow connection.