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Small Cabin Forum / Off-Grid Living / Questions on Upgrading a Rainwater Collection System
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# Posted: 3 May 2013 13:10

I have a small rustic cabin on Cape Breton Island in Nova Scotia. We are completely off-grid but not completely sustainable. We get our electricity from a solar energy system and our water from a rainwater harvesting system, but we use propane to power our fridge and for our stove. We're also planning to add an Eccotemp L10 tankless propane water heater to our water system this summer.

We are buying a new 400-gallon water tank this Spring as well (the old one was a rusty galvanized steel fish transport tank with a plastic bladder that we got for free and jury-rigged to kind of work, but we're moving up. The water we collect from our roof will be used for showering, washing dishes and watering plants in our garden. We get our drinking water from the supermarket.

Currently, we use a couple of basic Shurflo demand pumps powered by 12V DC to bring cold and hot (tepid actually) water from our main tank and a passive solar tank (a black dock float we also jury-rigged for the purpose, with unsatisfying results. Our water conduits are " water hoses. We are also planning to buy two new Shurflo demand pumps, the "Revolution" model, because it rates at 55 PSI as opposed to the 30 PSI of our base-model pumps and the Eccotemp L10 people say it will work better with a more powerful pump.

Here are my questions:

1. Here is my proposed water chain: gutter spout into INFLOW of water tank; one hose (cold water) comes out of the tank and goes to a 55psi demand pump and from there splits to one hose connecting to the cold tap on our shower, and another to the cold water tap on our kitchen sink; the second hose coming out of the water tank (hot water) goes to a second 55psi demand pump; from there a hose goes to our Eccotemp L10 tankless water heater; from there a hose splits into two hoses, one connecting to the hot water tap on our shower, and another to the hot water tap on our kitchen sink. Is this a good or the best way for me to set up my water system?

2. Shurflo sells a strainer and an accumulator tank that attach to their pumps. Is there any reason I need to buy these?

3. Should the pumps themselves be protected from the elements by being housed in a box?

4. The Eccotemp L10 is rated at about 2.5 GPM. But I am assuming that there is an inverse relationship between the flow and the amount that the heater can raise the temperature of the water. That is, the faster the water flows, the lower the temperature will be when it comes out of the tap. Is this correct? Since our low-flow shower head wants a flow of 2.5 GPM for a decent shower, is there a way to calculate how hot our hot water will get at maximum flow, assuming that the water starts at a temperature of, say, 55 degrees F?

5. Some water tanks come with a gauge that tells you how much water you have left. If we get a tank without this feature, can an aftermarket gauge be installed, and is there one you'd recommend?

6. Is there any point in insulating the water hoses since we're using the system only in the summer?

Thanks a lot. Please feel free to respond even if you only have answers to some of the questions.

Paul Spillenger

# Posted: 3 May 2013 15:54

!. Why 2 pumps? everyone I know runs a single pump, including myself

2. read the install manual
" Pump must use an adequate 50-mesh strainer
[such as SHURflo 255 series strainers].

No need for an accumulator..."

some pumps perform worse with an accumulator and other require one . these do not need one it is designed for intermittent use not long continuous high pressure runs.

3. they are fairly well sealed but i have not seen it printed anywhere that exposure to weather is ok

4. there should be a table or chart from the water heater mfg that shows the relationship of flow to water temperature including the effect colder inlet water has.

5, no idea

6. i might insulate just in case my pattern of use changed.

# Posted: 3 May 2013 16:28

NO 5 IF you put a tee in the out let at the bottom of the tank and add a length of clear hose running to the top of the tank and then folded over not plugged. You will be able to see the water level in the tank in the clear hose .
you should filter the water before it goes into the tank ,that way you needn't worry about a filter on the pump and any bleach you add will work much better ..

# Posted: 4 May 2013 10:33

I am building a similar system. Same components anyway.
I am going to use a sand filter before the rainwater reaches the catchment tank.
1. I'm using one pump to a manifold that splits the cold to the hot water heater, a sink and a washing machine.
2. the manual for the revolution does ask for a strainer. i haven't installed one. maybe that's yet.
3. you should protect your pump from the elements.
4. as per ICC, there are tables that indicate temp rise.
5. thx Just. I'm going to try that. beats banging the side of the tank and listening to how it sounds.
6. i'm insulating my pipes for spring and fall ... and maybe winter?

# Posted: 4 Jul 2013 18:14

Hi there, I recently bought a 10 acre lot in Richmond County NS with a plan to build a small, completely off the grid cabin. It has 300 ft of river frontage on the Inhabitants River and I can't wait to get started! I've been looking into permits and such, and as I'm not a lawyer it seems like a very complicated set of hoops to jump through. I hear that if it is under 215 square feet no permit is required any truth to that? What did you have to do before you could begin construction? Any help will be greatly appreciated.

# Posted: 4 Jul 2013 23:52

gottadream - see if your municipality has a website, mine posts all the requisite documentation online which was convenient, but not everywhere does that...

Otherwise best bet is prob a trip to the muncipal office.

# Posted: 17 Feb 2014 11:20

Hi Paul
We saw that you are planning to install a tankless propane hot water heater in your Cape Breton cabin. We're hoping to do the same thing this summer and are looking for someone to install the system. Is there anyone you would recommend around the Cape Breton area? Also, assuming it is now installed, how is the system working for you?

Thanks very much.


# Posted: 17 Feb 2014 15:09

I have the same basic setup. We use a 275 gal. IBC tank. I have a screen on the top at the water inlet but I still get some bugs in the tank. I use a whole house filter that is plumbed in before the pump. It works well and seems to protect my pump ok. I only use one pump. It is a surflo, but not sure of the model. It runs at 55psi. The IBC tank is clear so I dont need a tank guage. I built a small shed around it next to the cabin.

# Posted: 17 Feb 2014 18:56

Let me tell you about my system which might give you some ideas and also help with your questions:

I have a 375 gallon underground cistern. It is those elliptical ones that can be left empty underground. It is below frost line (upstate NY)

I installed this gauge on it (works perfectly) ?ie=UTF8&qid=1392680598&sr=8-2&keywords=water+gauge+rain+harvesting

I just used a bulk head and 1/2" pvc to allow the wire to come up.

The water comes off my roof and goes into a 4" wye. This is used as a first flush diverter. I drilled I tiny hole on the bottom and glues some gutter foam to prevent it from clogging. Water will come down, fill the 4" pipe (36" so it's a few gallons - my roof is only 144sqft) and then flows into the other pipe in the wye - which diverts the first flush. Right after the pipe -> I installed a 4" T with access (it is called clean put T) and I put several different layers of foam so it clears the water from junk and act as a mechanical filter.

I also stick a chlorine puck (for pools) in there so as the water goes by - it get chlorine shocked before it enters the tank.

In the tank I have a water pump (utility pump) that feeds an indoor 20 gallon tank. I did this, following mountain Don method, to avoid having my pipe freezing or needing to heat any pipes.

I flip a switch inside the cabin, my indoor tank is filled, and I click it off. Now I have 20 gallons in the cabin and no water in any pipe - no check valve in the utility pump.

From that I have an RV pump that feeds my shower, sinks, and toilet as well as my indoor propane heater.

Once I am done = leaving cabin after the weekend, whatever water I have in the indoor tank - I drain back into the cistern. I also blow all the water out of my pipes.

I am very happy with my system. Even though I haven't finished my bathroom yet so no shower... hh

# Posted: 17 Feb 2014 20:19


# Posted: 18 Feb 2014 00:04

I have installed a 1500 gal, 6000 litre, underground tank purchased through Barr plastics in abbotsford ( built by Graf )designed for burial and potable water. It's about 8' in diameter with a 24" dome. The water level tends to be 3-4 ft below ground level for frost protection. I take water from the gutters(metal roof) with "gutter guards" to stop big stuff, water is directed through simple filters made from 5 gal buckets, with fine washed rocks and no-se-um mesh on top to trap fines(easy to pull out and clean) then directed under ground using irrigation pipe to tank. Built in filter in top of tank to finally filter out stuff.(worst problem us pollen, this spring I will disconnect drains during pollen season) My pump brings water out of tank into shed and then through filter, then ultra violet treatment before supplying my place. I tried making screens in the drain area of gutters but found them too hard to clean. The bucket with fine mesh is my wife's brain wave. Good one! The 1500 gals, seems to be adequate for our area for all of our washing, showering and cooking needs. We still bring in filtered water for drinking.

# Posted: 18 Feb 2014 00:06

This is the bucket filter we built. One for each building.

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