Ouch! Hope it wasn't bad?

hi, thanks much for sharing all the useful info. can you also share how you measured the prevalent wind direction, and also the sun movement?

bro i didn't measure the wind speed, just the direction. just by using a flag, or a piece of cloth or throwing dirt or smoke you could see the direction that the wind is blowing.
anyway i used a piece of thread to get the general direction of the wind direction.

sun movement i checked using a compass, protractor, cotton thread and the shadow from a piece of pole.
timed the date, and time of measurement and took the angle of shadow to the magnetic north.
then verified the 3D model simulated sunshine and shadow to the actual location and orientation at the date and time.

sun simulation i'm using the built in features inside google sketchup.
verified that it's dead accurate to nearest degree.

reading back all the feedbacks i'm guessing i need to implement some sort of treatment before storage.
the UV lights inside the water tank is a hassle since i need to dunk the lights inside the large tank for illumination. make more sense to treat the water at the pipe before they're put inside the tanks.
easier to achieve high dosage of UV also.

and probably chlorine injection at the untreated storage if necessary, since those could be easily maintained.

ozone sounds like a hassle to implement and maintain. maybe i didn't read much about it. anyway i was thinking 3-5 micron cartridge filters that you could buy cheaply at tesco. i just need 2 prefilter location for the 2 collection tank (untreated water).

there will be a first flush system and a prefilter mesh to filter off the large organic particles. hopefully that will reduce the amount of large organic compound. while there might an issue, but considering that a lot of other countries are implementing rainwater harvesting system successfully, can get pointers from them.

i was looking to implement a variation of this:


if the water quality is still bad i'll do a chlorine injection at the untreated tank. and since the rainwater will now have some sort of proper treatment to them (tho maybe not to level of drinking quality), i'm also gonna use them for laundry.
that should make better use of the large storage.

did you use a first flush and any prefilter for this to happen?
i've been reading quite a lot and most of them say rainwater from the roof is quite clean without any harmful bacteria in them.

No comments on the earlier part which I think is sound since that's disinfection. But on this part I want to clarify. Rain water is indeed clean but the roof may not necessarily be. It will pick up stuff along the way which hopefully the first flush will clear. But microbially, that's not always so clearcut as the sludges in the drain pipes if it remains will always have unwanted contaminants. Typically in any home's roof top, if you see a lot of birds perched on the roof frequently chances are there might be guano deposits which means very high urea and phosphorus content which basically is a potent algae starter mix. Every time it rains, these things gets flushed down and depending upon the thickness and hardness of their encrustation. Maybe less of a chance if roof is very hot. But just observe it on your current place esp the neighbour's roof and gauge to what extent there are these things and possibly others (dead leaves, etc).

Rainwater is indeed clean, I will happily bath in freshly collected rainwater, and will even drink fresh rainwater collected directly in a clean glass. (provided this is in kampung area, no acid rain problem.)

There is just an issue if you need to store them for extended period (e.g. > 1 week). The organic matter is the water (bird poo, dust, dead leaves etc) provide food for bacteria growth, which will start off a food chain. Insect larvae etc will feed on the bacteria etc. etc. This happen very fast in our warm weather.
Most of these will be heterotrophic bacteria, generally they are not likely to cause disease. If you don't bath and drink OK.
Algae is not a problem if you close your tanks and no sunlight.

Worst case scenario you get foul-smelling water that might cause a rash to people with highly sensitive skin. And you might see some larvae of sorts swimming in your toilet bowl after a flush.

And you will likely be storing, since your peak collection is >12000 liters, enough for > 2000 toilet flushes. That's two months worth of pooing and peeing.

Installing a UV flow cell and a prefilter is a good option, if you don't mind the cost of extra plumbing and tanks. Make sure the uv cell is properly sized for the correct flow rate.

Otherwise I will just drain it regularly and add chlorine once a week if I need to store the water. Connect a huge shower in the garden and play with the kids.

If you want to use for laundry best include another filter in the laundry line. Fine particles and rust can do hell to white cloths.

If I do this, my actual worry is the extra 12000 kg sitting on my roof. But then again, condominiums probably have 100,000 liter tanks on their roofs.

This is a fresh water. Not even using rain water.

The point is, the harmfull bacterial. How to makesure your toilet bow stay clean from harmfull bacteria. If you insisting of using rain water, just makesure every drop of it is bac free water.

From your implementation, it look like very high cost inorder to use rain water. Your monthly consumption is high for water?

thus the importance of first flush system.
most other guides doesn't mention how much is needed to be flushed from use prior to storage, but this texas guide does have a formula for calculation:

warning! boring alert.


and the all important formula:


2749 sqft of roof cover on one side, and 2047 sqft on the other.
i'm gonna have to flush ~30 gallon and ~20 gallon.
how am i gonna flush that much i have no idea. a simple 6" downpipe, 6 feet high will only hold ~9 gallon of water. multiple downpipes in series will have added benefits i reckon. less chance for the contaminants to go through.

constant flowrate flush system could be implemented by this aussie system:

but it needs a leak-proof downpipe for it to work. gonna pass.

and for those that's interested in adopting a gutter screen with the cheapest amount of money, this might do well:

an aluminium mosquito netting should be small enough to filter most of the debris, cheap to buy, readily available and should last quite a bit.

i did considered an underground tank. but those would be a hassle to clean. but since they're on the ground it'd be easier to to add salt or chlorine manually. skipped since it's hard to remove the sludge after a while.

anyway while the system is able to store 12 tonne of water, only 6 tonne will be rainwater. the other 6 will be treated tap water. 3-3 or 4-2 if there's a need for reconfiguration. the master bedroom will have a large tub that will take 250-300 gallons of water to fill. that is, if what i'm reading is correct. so the tap water cycling should be enough if my wife fills the tub once a week.

as for the rainwater cycling, guess i'm gonna have to recycle them back through the filter and UV once a while. will be implemented as part of the design.


okay you got me concerned. is this because of too long storing the water?

i'm not planning for a costly system. if it's too expensive might as well scrap the idea. monthly consumption isn't much anyway, my previous house we're paying the minimum bill of RM6 every month.
the idea of harvesting the rainwater is because the roof structure is perfect enough for it to be harvested. i'll try and keep the cost down else i'll just scrap it.

3000 sqft so many rooms and bathrooms. Sounds small to me. I am 2200 sq ft living area and I just have 3 bedrooms. 2.5bath, 2 living area and a small office. Of course I have like 300 sq ft of unfinished storage area.

Too many opinion confusing you.

Your idea is OK. So just go ahead.

If you dun mind the capital outlay, install a uv treatment, gutter shield etc. Guarantee cantik.

If dun want to spend money, just spend a bit more time to maintain.

My opinion worst case scenario you get some not nice smelling water with a few larvae, but perfectly OK to flush toilets.

Rm6 only? You talk like serious implementation for a high usage? Thaught your monthly bill like rm50 or rm80.

From your plan, the monthly cost for this rain harvesting is already probably cost rm5. A monthly change filter, uv light depreciate and energy cost. How to keep it low?

It happen many many yrs ago. Not serious. But enough to educate me. It is probably of long holiday back and didn't clean the toilet. After this, did clean the tank and disinfect everything.

that's an old plan. been scrapped for a single storey design. the updated floorplan is in this thread, somewhere.
yes it's a small house. can't afford bigger because i'm poor.

the lots of varying opinions is quite hard to take all in.
but it's all good. because of all of the feedback that i'm planning for a recycling process to move the rainwater through the filtration and UV to avoid them stagnant for too long.

old house bro. back then it was me and wife and a baby. 2 toilets. no garden. no tub. no maid.

with the planned planter boxes, garden, growing up child, tub and all; i'm guessing the water bill north of RM50.
while that is still quite low, and the rainwater system won't break even ever, i rather use the rainwater for something.

after all, the house is an experiment.

Don't worry too much la.

Suggest just go for simple rain harvesting. Net trap-->micron filter-->storage + chlorine injection. If good than expand it to better system. If no good, chop off the pipe and convert to clean water tank.



In my planning design of piping system, I always treat the water as very low consumption and is always the lowest cost in my monthly bill.(Free) I pay RM6 from day 1. And now for 7yrs, totally free. So

1) running an electrical applicance to get a free water is waste to me. Cause electric is expensive than the water.
2) Try best to design the backup piping system, etc using gravity or auto run mechanisms without intervention from human or using electrical parts.

My way of seeing the rain is a free water. If my monthly bill require to pay just to get a free rain water is a waste. A filter change cost RM4, chlorine probably RM0.5 and pump running cost RM0.5. Total up RM5 monthly bill for a free rain water. Why not just pay additional RM5 to syabas to get another 5m cubic of clean water on top of my monthly water bill? No money invest, no maintenance, no worry about bac, syabas happy.

But this is just me who spoilt by the free water thinking. He.....

I got 4 kids, wife planted loads of don't-know-whats, 4 midi -fish ponds, wash my own cars - monthly water bill seldom exceed RM10. Now I pay Syabas RM50 beginning of January, until Dec no need pay, got credit somemore.

Water is cheap, but I am also installing a cheapo rainwater harvest - just to remind myself and the kids not to take anything for granted. And of course, it's just fun and gratifying to do these sort of stuff.

Will start with one 300 liter tank, sitting on a concrete bench 3 ft above ground behind kitchen. Water collected off gutter from ~1200 sf of roof, and will be used mainly to water my wife's herb garden and other plants using irrigation pipes and gravity flow. And washing the car porch.
The concrete bench is to house my two gas tanks, might as well make it real strong and plonk the water tank on it.

Will fabricate most of the stuff like first flush valve DIY. Long term plan if lots of rain, plan to install another tank and a pump to pump the water up to main tank, after chlorine treatment and 3um filtration.

Won't break even in my lifetime, but, you know, fun stuff to do.

final design? alot of walls.. not my style.
I like open concept

leave my footprint here first, very interesting :3

first of all, did you get a SI report for your site prior to your construction of foundation. this is dirt cheap to get and certainly helps you the hassle of differential settlement in the long run.

I think your pile qty a bit too much. frm the SI, we can know if your soil is strong enough. A raft foundation will do or combination with shallow pile which should cost a lot less with more provision for future upgrading...say 3 sty

Just my 2 cents.

Anyway, gr8 sharing here...keep it up. can't wait to see the end picture.

This post has been edited by Vip3R: Nov 27 2014, 02:31 PM

fuh. it's been 15 pages. and 25,000 views. garnered quite an interest eh?
too bad i'm not earning anything from all the traffic.

all future updates will be relegated to my blog. further documentation on the construction, rainwater system, electrical & plumbing systems, and automation will done at my site to help isolate all the different topics.
serves larger viewership and avoid daily update/posting from irritating other forumers.

as such, this topic will be closed.

thread reopened.

the sheer amount of incorrect information and wrong assumption in these parts are just breathtaking.