House Water System

Posted by on Sep 4, 2007 in Life Support Systems | 2 Comments


We are quite reliant on a continuously available supply of clean, clear healthy water. With this awareness we have designed a resiliant integrated system to be sure we can trust it flow when we need it. This is reserved exclusively for rainwater from the roof of the house.


The context.


We live in one of the poorest council areas in Australia – Kyogle Council has more bridges and roads on hillsides per person than any other. These are essential and expensive,




So luxuries of the centralized urban experience like drinking quality water delivered to your tap at about a dollar a ton are low on the rural fringe. If you want to pass the buck, it costs $160 for 6000L of chlorinated town water to come to you on a truck.


Fortunately we have our own house roof that is 11m x 12m. That is giving us 131 square meters of catchment.


We do not pay per litre at all. We expect about 1300mm of rain a year here, free of charge. And that's enough.




The maths of a tin roof;


1m x 1m x 1mm = 1L (Love the metric system!) 11m x 12m x 1300mm = 171,600L total for the year.


That's a lot! But it comes in downpours, especially during the hotter subtropical summer months. As we are quite reliant on a continuously available supply of clean, clear healthy water we have designed a system to be sure we can trust it to be there whenever we need it.


How much do we use?


Before we had electricity and a functional rainwater system, we washed our clothes by hand in creek water. This was a time consuming, tiring job that gave us inconsistent results. We now grow salad greens in our twin tub. With the arrival of electricity Kirrah's father bought us a house warming present;


Our washing machine. It uses 73L a wash and we use it about 4 times a week. So 292L a week. A shower uses 6.66L/m. We have only recently fitted a good shower complete with hotwater plumbed into the woodfire. So the data is still being collected. Today Kirrah showered for 6 minutes and 15 seconds. I Showered for 3 minutes and 30 seconds so 9 minutes 45 seconds. So 65L/day. Averaged to 330L a week. We also bath. Each bath uses 75L we have about two a week. So 125L a week. We drink at least six litres a day. We fill a stoneware filter by hand with a jug. 42 L a week. We wash the dishes everyday and that is about 20 litres so another 140L a week


That sum total is 1199L a week.


We are able to moderate our usage. As feedback comes very directly from daily experience.


Recently it didn't rain for two months. At the tail end of that small drought, we washed our clothes in Nimbin, bathed in an inch of water and rarely used the shower. We continued to drink six litres of beautiful filtered rainwater every day.


That experience motivated us gutter the larger side of our roof, (a job that hadn't been done since the house was built in '94!). Several days after we connected the new system and plumbed it in – it rained for 7 straight days. We recorded 175mm of rain. That was enough to fill our concrete tank to the brim – 23,000L.


Catch and Store


We have 46,000L's of rainwater storage. The 46,000L is made up of two 23,000L tanks. The high side of our roof is so high that I would not climb a ladder to clean the gutters out.




So I had to buy several lengths of a completely self managing guttering system.




This is a photograph of an offcut, It has special filters that fit in those holes. Water enters the centre channel of the guttering through the filters. Leaves cannot and simply blow off. This is also the side of the house that fire is most likely to approach from (North North-West) I consider this additional expense appropriate.


A concrete tank is connected to the gutters. There is a poly tank at the top of the hill.




These two tanks are connected by a single 1 1/2" poly pipe. This pipe allows water to be pumped up to the top of the hill and then to run back down under the pressure of gravity into the house.


There is a special procedure to manage this two way connection.



Pumping Water




Before beginning the procedure – check the solar power and battery status. The pump is rated at 700w – a motor this size we can only use during the peak of a sunny day, unless in emergency. This way the panels feed the pump and not the drain the batteries. If there is full sun and the batteries are high (90%+) we can move on to the next step.


Make sure there is enough water in the concrete tank – this is a simple visual inspection through the top. If the pump is allowed to run dry it will be damaged.


Now the details; First turn off the master red tap, this stops water running down the hill from the poly header tank to the concrete base tank. Then turn off the smaller red house connection, this prevents backflow from the house if someone turns on a tap while pumping. Now we can open the gate at the base of the concrete tank – open it fully.


If the top tank has been fully emptied the pump needs to be primed first. To prime the pump, open the red master tap. Otherwise; plug in the pump and then immediately open the red master tap. This should be done very closely – best done with two people.


The pump is now pumping water up the hill.



While pumping, keep an eye on the solar system readout. Keep the battery voltage above 23.5v. Best to pump while at least 20+ amps are coming in from the panels. The normal range for the pump load is 45-55amps.


To Safely Stop Pumping Water Pull the plug for the pump, quickly turn off the red master tap. Now carefully turn the concrete tank ball valve shut. 

Now turn the red master tap back on and finally the house mains tap. If the Tank Valve is left open, even slightly, water will run back down the hill from the header tank and potentially be lost as overflow, as well as causing all sorts of problems with the hot water pressure system.


Pump Diagram

















Where does it go?


This rain water is plumbed into the bath, the shower and the kitchen sink (and their respective wetback hotwater system). The washing machine and several taps are connected to just the cold. The kitchen sink has only recently been plumbed into hot water thanks to available light, assistance and motivation.


We use a silver and activated charcoal ceramic gravity fed filter for our drinking water. We jug this from the kitchen tap several times a day.


Chopping wood and carrying water are two of the grounding day to day jobs of our reality.


Storage and technical Specifics There are 8 rings on the poly tank, each ring is 2835L. A knock on the side of the tank will tell you how full it is.


We have about 7m of head, our pump Davey is model number xf221 and will pump about 200L/min or 12,000L/hour.


It pulls about 1050W(P1) and outputs about 780W(P2) of pump – the rest (270W) is dispersed as heat and noise.


P1 * time = pump Wh


1050w * 1h = 1050Wh


We have a 24v DC solar system which displays usage in amp hours. This is then converted (inverted) at 90% efficiency to 240v AC electricity that the pump wants. Running the pump for an hour consumes 1050Wh / 24v = 48.125 amp-hours and pumps 12,000L.


To give a rough guide on how much water is being pumped it is possible to monitor each amp hour used on the solar system readout.


1 hour is 60 minutes. So each minute the pump is on it uses .802 amp/hours and pumps about 200L of water. Therefore each amp/hour is approximately 160L of water moved to the top of the hill.


I keep a record of this change in a log of water usage. The system is being constantly refined to our needs and the environment. I am currently very pleased with it. Water and Life.


Grey water


Grey water is treated on site in a special bed of Arrowroot, Taro, Comfrey and Tansy. This system was designed and installed on a work activity day organised by the Permaforest Trust. The kitchen and the bath are run through a grease trap. The bath needs an S bend installed to prevent swampgas from coming back up the line. There is debate in the greywater sphere about the effectiveness of greasetraps as they encourage anaerobic decomposition, however they are still the legal standard. From the greasetrap water feeds into three separate beds built on terrace. The root crops are not to be eaten, but was can use them as rootstock for areas designed for food production. The system is currently thriving and experiencing a burst of spring life. Lomandra and Vetiva grasses have been planted to keep out invasive grasses.


A full and complete writeup of the process is at the House Grey Water System.




Today Kirrah and I plumbed under the house a pipe that connects the wood fireplace water heater storage tank to the sink! We no longer need to carry 15 sloppy litres of hot water from the bathroom to the kitchen sink to wash up. We haven't done that much more washing up – but it has made the whole process a lot easier! I still carry 15 litre water buckets around everyday to water plants. Except tonight as it is raining!


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