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Home Forums General Discussion Need Input On Converting "Shed", To Have Running Water (Totally Off Grid) Reply To: Need Input On Converting "Shed", To Have Running Water (Totally Off Grid)


the shed specification says 12 or 14 foot width and length is not given, but looks like 20 feet mol. You can scale from these numbers if I used the wrong ones: 12X20 is 240 s.f. so one inch of rain gives you 20 cubic feet of water (150 gallons). It depends on how much and how frequent your rains are – how much do you need to store. You can find data for your local area total rainfall and get an idea of total rainfall per year and evaluate if that is enough water for your needs (assuming you can store enough).

Let’s say you get 50 inches per year and store it all. That is 50×150 = 7500 gallons or about 20 gallons per day. But you don’t need a 7500 gallon tank if it rains a little every day – just 20 gallons would be enough – you use it as you catch it. If you have a dry season, you need storage to get through it. Simple enough.

For the USE of the water, you are probably accustomed to city pressure which runs around 30 psi or more. That is equal to an elevation of about 60 feet. If you collect water at the downspout elevation in elevated barrels then you won’t have much pressure for using conventional plumbing fittings – use larger pipes and valves or you won’t get flow. If you want more pressure, you can pump the water to storage at higher elevation, or pump it up to pressure as you use it. The energy cost will be about the same either way. You can pump water manually (energy from muscle instead of solar or etc.). It is significant work. You can actually bail water from a storage barrel and pour it into an agriculture sprayer (devoted to showering only), pump it up and spray yourself down. 100% manual powered. This saves water too since you will NOT waste a drop!

Solar will run a pump. Most panels these days are made for grid-tie, so their voltage is not well matched to battery voltage. MPPT controllers are great for making the most of solar panel output, but they are expensive. If you hook up grid-tie panels (higher voltage) to conventional 12 volt batteries, the panels will just operate at the battery voltage, so they will not necessarily damage batteries (though they can if they put out more than the batteries can store) – but also the panel capacity may be somewhat wasted. You can prevent overcharging with a conventional charge controller that is much cheaper than MPPT type, since solar panels are getting cheap enough that you can afford to waste some capacity in exchange for lower investment. If you want 360W but no MPPT, then you might wind up buying more like 700W of panels (they would be able to run at 25 or 30 volts, but you actually connect them at 12 or 14 volts and correspondingly get only half their rated wattage. You spend more on panels and save on controller – you have to work out the details on that.

You can probably run a pump directly from panels with no battery but you’d need some other kind of controller I guess – others would have to step in on that. I don’t know about it.

There are 12 volt pumps at marine stores, but most are 110 volt (or 220 volt in europe). You will need an inverter to run such pumps from batteries. The inverter capacity will need to be more than double the rated motor capacity since motors have a large starting current surge, and generally have a high “power factor” meaning they appear to consume more wattage than rated because of “inductive load” which causes the inverter to operate inefficiently. You will have to look into specifics for your situation.

hope that helps – probably just makes more questions . . .