mwp
Member
I'm seeking opinions on a suitable filter for a rain water system.
It will initially supply toilets and washing machines.
I'd like later to plumb it into hot water for showers.
What types would be best?
Carbon?
Resin?
Combination?
To what micron would be acceptable for showering?
My budget would be under $400.
David
Member
mwp said:
I'm seeking opinions on a suitable filter for a rain water system.
It will initially supply toilets and washing machines.
I'd like later to plumb it into hot water for showers.
Don't filter the toilet at all it certainly does not need it.
Or is someone going to drink from the bowl? 
I did the whole house, because it's in town I did put filters in but mainly because I like removing the town grime from my drinking water. I don't use that water for flushing I use processed grey water for that. (Toilet flushing can be 1/3 or more of all water used in a house. (To do it right runs up a few thousand dollars)
For filtering of tank water I have 20" x 4.5" filters x 3 in a row 20 micron > 5 micron > 5 micron activated carbon with "silver" (refillable) the "silver" stops the carbon turning into a bacteria haven (needed for tank water) if filtering. $500 is not enough, after a pump, decent spring loaded check valve, pressure/flow switch, plastic pipe, etc at least $1000-$1500 would be more like it to do it right, and that's using ebay cheaper stuff.
Don't skimp on the filter container system or they will almost certainly leak otherwise. Always get a spare set of filters.
mwp said:
I'm seeking opinions on a suitable filter for a rain water system.
It will initially supply toilets and washing machines.
I'd like later to plumb it into hot water for showers.
Are you inquiring about an existing RWH system or is it for a new yet to be installed system?.
How many tanks are there?
Chip
Member
My family has lived on unfiltered rainwater for decades and we have ever had any ill effects. When tanks are low, heavy rain can churn water up a bit and it's a bit cloudy but otherwise no drama. Filters may be good for peace of mind but can be expensive to buy and maintain and they consume power to drive the water through.
mwp
Member
Diver said:
Are you inquiring about an existing RWH system or is it for a new yet to be installed system?.How many tanks are there?
Thanks,
There are two tanks - each 9000L. So, 18000L total.
The hot water system is already installed.
I'm not intending to drink or cook with the water. The shower would then be half mains (cold) and half tank (hot).
I've drunk tank water with no ill effects, but the SO is insisting on filters.
Benny
Member
Could you just put a few bits of 90mm PVC in line that look like filters to fool the SO (whatever that is !) Does the water come from clean roofs ? Does it have time to settle in one tank before decanting to the second (from which you draw). I can't see why you'd need to filter anything other than drinking water.
johnmath
Member
I put in a washable 1 micron pleated filter for around <$100 and works on gravity feed pressure for my drinking water. It is there to take out visible muck only. I have only cleaned it once in several years. On my house supply, which is pumped, I don't have any filtering. The toilet bowl does get a dirt line around the water faster than when on main water, but that is the only difference we notice (apart from the niceness of soft water showers and clothes and dish washing).
See: http://watershop.com.au/standard-pleated-polyester-sediment-filter-cartridge/
gabs247
Member
Don't want to hijack your thread, but I'm considering a similar situation. Building new house, just bought a 10KL tank to plumb the whole roof to, and was hoping to plumb the tank to the whole house. I'm in Suburban Adelaide, and using Tankulator indicated 10KL was optimal for expected usage/rainfall, but I am a bit concerned about bird droppings, pollution, dust settling on roof and getting into tank. Planning to put in good FFD/GutterGuard devices on the downpipes, it will be a wet system so don't want that stuff sitting in the pipes. In a way, hedging my best as probably 50% of year tank water, 50% of year on mains...which one is better in Adelaide considering 50% of the state use tanks?
Any thoughts on using the water for the whole house in suburbia? I want to put in a good filter, but I'm talking actuated carbon with micron filter (interesting point about the silver). Also, want to put a better filter on the Kitchen tap for drinking water...
In terms of HWS will it be continuous or tank, as tanks supposedly kill the nasty bacteria by heating up to 65+ degrees C; we're getting continuous.
Hi mwp,
I checked your old posts (and some PMs) after posting. I decided to leave my post so that others would know your set up.
I gather that the SO is AKA SWM.
A HWS would normally kill harmful organisms but I will have to inquire about the instantaneous type.
Interested to read that johnmath's 1 micron filter works on gravity feed. I am about to connect to my HWS (a long time coming) and was considering a 10 micron. If the harvesting system is well set up and the water is not for potable use, one isn't really needed but for the little cost involved...why not?
The trick with harvested water is to deliver good quality water to the tank and draw even better quality water.
Do you have leaf diverters?
Are the tanks used as a settling system, that is, is the water fed into one tank and the decanted water transferred to a second tank that supplies the pump? This will supply water that should be free of suspended solids. When the tanks are fairly empty, it is even better to let the water settle for a couple of days before opening the balance line.
Would you consider fitting a simple sediment trap into the horizontal wet system pipe? This is cheap and easy to do with off the shelf parts and it will capture most of the bed load (that moves very slowly). I can post instructions.
If you are in an area that is getting plenty of rain and the tanks are full, you could also make a simple syphon tank cleaner and give the tanks a quick clean.
To do this, use a length of 20 or 25 mm PVC pressure pipe that fits under the tank's roof (makes the pipe easier to move around) and fit a PVC pressure faucet elbow (one end is threaded) to the top. You then screw a poly director into the elbow and clamp a poly pipe over the barbed end. All you do then is prime the hose and let it fall so that it syphons while you move the PVC pipe around.
It is best to hold the pipe against the bottom of the tank while you prime. You will probably also have to fit the poly pipe into a sleeve so that it doesn't kink at the top of the tank. Also, move the pipe around slowly and keep it off the very bottom of the tank.
Nothing like starting with clean tanks.
tom rickard
Member
I found mixed research results on using silver with the carbon filters, general consensus is you need to keep adding silver on at least a monthly basis for it to be effective. If i wanted the best filtration system, i'd go with a UV treated system. For now i'm comfortable with 2, 20" by 4.5" filters, one sediment, one carbon. I'll change out the carbon filter every 6 months. All of our water goes through these filters. Filter kit cost around $220, and the carbon filters are around $40.
mwp
Member
There are leaf diverters, a filter on the exit of pipe feeding the tank inlets. Then two filters at the top of the tank. The pump draw outlet has a floating filter, so water is drawn about 20cm from the top water level.
It's a wet system (that in hindsight I should have used 100mm pipe instead of 90mm), but it does work OK.
There is a buildup of fine dirt on the bottom of the wet pipe as seen from the inspection cap.
I flush the charged system to the street during dry periods.
Up-shot of all this is that the rain water is pretty well filtered before it gets into the tanks.
SO significant other = SWMBO .
The toilet and laundry I'm not fussed about, just showering hot water.
So, I'm thinking two filters, one resin and the other 10 micron carbon should be more than enough.
Thanks for all the inputs.
mwp said:
There are leaf diverters,The pump draw outlet has a floating filter, so water is drawn about 20cm from the top water level.
I flush the charged system to the street during dry periods.
I'm thinking two filters, one resin and the other 10 micron carbon should be more than enough.
You have an excellent harvesting system. I think that you have summed it up very well.
I run no filters other than basic tank top screens and a leaf diverter on our rainwater system. Our system supplies the toilet and the washing machine. The outlet to the tanks is sufficiently far from the inlet that any stored water has a long settling time so we seem to end up with relatively clean water coming through the system.
dlvb19
Member
I am running a wet/charged system with no filters other than tank inlet screen, supplies whole house. Has been several months now and no issues. Fortunately there are no trees around so we get mostly bird droppings and dust. Outlet is 170mm from bottom which in Rhino Tank standard. Don't anticipate any issues unless the water level drops below half and the incoming rain water stirs things up. Our tank also has a slide valve at the lowest point so we can flush the charged pipes periodically. There are a bunch of flies floating in the down-pipes but I'm not worried, I just don't let my partner know 
. Everybody needs to stop being so antiseptic and build their immune system. Should be more worried about salmonella in your chicken, BTW go vegan
Tank will need a de-sludging every two years or so which I can do myself with a scuba mask and a puddle pump.
No matter the mechanisms implemented, sludge is inevitable. Go with it!
Might one day consider a fine particle mesh filter on the washing machine to stop any potential valve soiling. Other than that....laissez-faire
Johnnojack
Member
2nd that. No filters on delivery side for 7 years and just a mm or 2 of silt on the bottom of the tank. Gutters are kept clean and have a fine screen in manhole of tank where pipes enter, catches insects and bird droppings. Wet system is not up to Diver's specs. but with regular flush out is OK. Only problem I have had is the tiny filter on Rinnia HWS blocked a couple of times within a week yet had gone for 6 years without blocking. If the tank ever gets low enough I may install a floating pickup of some kind. Will probably make one, not rocket science. Have been drinking rainwater for 60 years and hasn't hurt me yet. Can't remember when I had a stomach upset last but it was a very long time ago. If I lived in a more industrial area it would change my views somewhat. An irrelevant comment as I would not move to such a place.
gabs247
Member
What's considered Industrial? Our house will be in Suburban area 7km north of Adelaide CBD. 300m from a main road, lots of mainly bus/car traffic but commercial zoning along it. 170m from another arterial road with less traffic. I'd say the air would have general pollution.
Any thoughts on whether people think this is too "Industrial"? And whether it's best to avoid plumbing a tank to the whole house, or just putting better filters on the end of it, in combination with FFD/Leaf Filters? Again, sorry to hijack post :S
Greg
Member
I contemplated whole house but then wondered why I needed it. Eventually decided on a filter tap in the kitchen for the paraniod people. The rest of the systems is 85kl combined tanks, gutter mesh, tadpole downpipe filters (no longer available) double SS mesh on tank inlet. I also went for a floating intake to the pump (float keeps flexible hose just below the surface so little sediment uptake) then a backwash filter prior to the pump that keeps the pipes , HWS and importantly ceramic seat taps grit free. I reckon thats enough filtration
The system is "wet" and gets drained manually.
First flush diverters are a tricky subject as they can result in high yield losses but in some situations, they are essential.
Most use a 90 mm PVC stormwater pipe for the capture chamber. The nominal size is measured as an outside diameter, the flimsy walls (less than 2 mm thick) giving a volume of 5.8 litres per metre. A 1.5 metre long 90 mm diameter flush pipe holds 8.7 litres. This is little more than .2 mm of rain to flush a harvested 40 sq m roof area. Hardly enough.
The slow dripper that most first flush diverters have results in much higher yield loss than what the flush chamber captures. One drip per second is approximately 13 litres per 24 hours. Note that this is not based on Apothecaries' measure, it is real life. Most slow drippers I see run as a steady stream and during breaks in the rain, the dripper continues draining the flush chamber.
So...not only do you need to capture more initial first flush, the 'slow' dripper is wasteful. They can also block and emptying a blocked chamber can be messy.
Ideally, you should use a diverter that can be manually drained. Two or three diverters can easily divert to the same drain valve that can also be left open for a short while during initial rainfall after a dry period to increase the amount of initial flush diverted. You will need leaf diverters to use a manually drained flush system unless the flush chamber's bottom screw cap is retained.
For best results, look at having a settling tank system and a WaterNymph or similar product that takes the best quality water from about 200 mm under the surface.
You should harvest the largest roof area possible but this invariably results in tanks over topping when the inflow capacity exceeds the overflow capacity during a storm. This can be fixed by using a syphonic TankVac that drains through an 80 mm DWV pipe at 9 litres per second once primed. It also draws the overflow from the worst quality water and sediment off the tank's floor, substantially improving water quality. A win, win.
Greg C
Member
You will need filters. We have first flush diverters and then the pumped water has a filter before the Rainbank controller, then after the controller a 50 micron then a 10 micron carbon filter. Our tank water feeds one side of the house which means bathrooms, HWS so you brush your teeth in it etc. It looks perfectly clean in a glass but look in the toilet cistern and there is a fine coating after a few years
Tankie
Member
Sounds like mwp has a well-designed harvesting system and the water entering the tank is going to be as clean as can be expected. If you're setting this system up now with new pump etc. I would pass the water through a disc filter on the way to the house but wouldn't be too bothered about any further filtration. For laundry and showering I don't really see the point
But a pleated cartridge filter would be within your budget and is easily maintained. Make sure if you have an external filter housing that it's light proof - otherwise it creates more problems than it solves!
