When I decided the water tasted better a few maggots changed my mind. The neighbour came and emptied it and there was a dead possum in it (a whole decomposing one). He then decided we could use the water that supplied the farm, which was a new set up from up the top of our 1km high hill. So the pump stayed turned off and the tank never used again. He plumbed it in and the pressure from the top feeds the header tank.
tweake,
Dec 19, 4:29am
simple problem with that is the flow off the roof is that fast that it will stir up all the crap in the small tank and push it all into the main tanks. your better to pipe it to the big tanks that are big enough for the crap to settle out.
the problem with filters is getting one big enough to handle the sheer volume of water that comes down and that they block up fairly quickly. expect to be cleaning them after every rain. something like a leaf catcher is handy if its self cleaning and just gets the big bits out.
best thing to use is tank cleaner overflow system. basically the overflow draws water from the bottom of the tank. this sucks up most of the crap and pumps it out whenever the tank overflows. i made a crude version for mums house and it works well.
harm_less,
Dec 19, 4:51am
Another option is to have the tank/s filled via an inverted siphon. In other words the roof downpipes travel underground until rising to an inlet near the top of the tank. This gives you a low point in the pipework where sediment and debris will settle which by installing a removable off-take on the low point which can be used to empty out the rubbish prior to rainfall events. The putrid leaves and debris that is emptied out of such a system is proof of your not wanting it in your tank.
You will also require filtration between the tank and your house, and particularly if you've got plastic tanks install a neutraliser (downstream of your filters) to prevent your hot water taps leaving blue stains. (Concrete tanks leach lime so a neutraliser isn't required). https://www.nzfilterwarehouse.com/product/372012
apollo11,
Dec 19, 4:59am
I'm also planning on making an overflow suction cleaner. And you are right about flow, in a decent downpour the 100mm inlet to the tank (charged system) just isn't big enough to cope with the volume of water.
tweake,
Dec 19, 5:42am
a removable take off is a good idea as a lot of homes have that pipe setup. however the catch with that idea is you need to "empty out the rubbish prior to rainfall events". most people tend not to do that or want to do that. it gets cleaned out if it gets blocked up. maybe on a service schedule once a year. also i suspect with a decent rainfall it probably gets washed out fairly well and into the tank. for stuff to settle out water speed has to be really low.
harm_less,
Dec 19, 6:11am
We had a horizontal low section of close to 8m in our last place. That collected plenty of debris, with minimal finding its way to the tank. I doubt a typical roof's water catchment would run swift enough to self clean a reasonable length like that with a 2.5m vertical rise required to the tank inlet, keeping in mind that the whole section is permanently full of water so water velocity is restricted. The same principal is used in roadside stormwater sumps and works well there.
tweake,
Dec 19, 6:42am
idk, mums is 30 odd meters long, never been cleaned in 40 years. never blocked. tons of crap gets into the tank. tho its got a fairly decent roof area. work is short, big drop in height to the tank and big roof aera ie big 2 story house size. that absolutely fires the water out, to the point that it stirs up 25000l tank. depends on the falls, how much rain, size of pipes etc. ymmv
apollo11,
Dec 19, 7:17am
I did think of drilling a small hole close to the bottom of our charged system to drain it, because we do get a small about of green slime growing in the downtubes- from what little light gets to the surface of the water there. But it really is quite a volume of water that would need to be recharged each time, so rain showers would be wasted opportunity to collect water. We have had no issue with water quality or sore tummys, even though I haven't gotten around to changing the uv lamp for years. We have a 100 micron and a 1 micron filter which get changed every couple of years and they seem to work OK.
harm_less,
Dec 19, 8:44pm
Not so much volume as you are thinking I suggest. A 110mm pipe holds about 57L per 6m length, so about 0.5mm rainfall on a 100m2 catchment.
apollo11,
Dec 19, 10:14pm
Our charged system is around 30 meters in length (does a loop of the house), plus the volume in 5 80mm uprights. i work it out at around a third of a cubic meter of water. Our roof gathers around 130 liters per millimeter of rain, so we are losing the first 2.5 mm of water every time it rains.
harm_less,
Dec 19, 10:34pm
Yes but as you said earlier your storage capacity is ~50,000L so 300 odd litres is neither here nor there and really only applies for flushing a couple of times a year.
apollo11,
Dec 20, 12:17am
But we can have months of occasional light showers in the Wairarapa over summer, and it's a long wait for a water tanker. I've got more and more bloody gardens to keep alive over the dry months, hence my reluctance to waste water. I even have a setup to divert rinse water from the washing machine during the dry season.
witchyt,
Sep 1, 10:09am
We're in the Waikato, we have 2x 25000ltr inground concrete tanks for 2 adults and 3 children aged 4 to13, supplied from a 350sqm roof only. We get very low by the end of summer, but tend to be ok with what we have.
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