One of the first things you realise in any off grid set up is how much we take clean water for granted. It’s literally “on tap”. Soon after we built the Log Cabin at Century Wood I installed a kitchen sink with a waste going to a gravel trap dug into the ground behind the Cabin, and a tap supplied from a water carrier. After 15 years of this set up, I decided to upgrade it with an on-demand pump and a better tap.
The next photo shows the original set up with a shelf for the water carriers filled at home. Lengths of flexible plumbing hose carried water from a brass connector in the wall of the water carrier to the tap. I turned the carrier on its side on the shelf and gravity created enough pressure to drive water down and up and out of the tap.
It worked well enough but there were always some limitations. The seal at the carrier was never perfect. The tap I installed didn’t reach properly into the sink so you banged your hands when you washed them. The small drop in height from shelf to tap didn’t create that much pressure. You had to lift the carrier up onto the fixed size shelf, which ruled out heavier carriers with wheels in the future.
Earlier this year I saw an advert for a USB battery tap with built in pump. That started me thinking about solutions with pumps. Eventually I settled on the on-demand 12V pump below that I can power from the Cabin’s 12V circuit. I’ve also been upgrading the 12V circuit to allow LiFePO4 batteries, more solar panels, and my generator if necessary so that I can have more power-hungry devices. The on-demand pump runs automatically while the tap is opened and the water pressure drops.
The pump is attached to one side a small wooden panel, with the 12V supply switched so the pump can be isolated when the water carrier isn’t connected. The switch unit is supposedly water resistant just in case. The low-pressure inlet side uses flexible 10mm silicone hose which runs to the water carrier, and the high-pressure outlet side uses braided 10mm pressure hose that runs to the tap. The high pressure side needs jubilee clips to hold the hose in place. I also put one on the low pressure side to make sure the silicone hose doesn’t get pulled off if I catch it.
You can see here the high pressure hose on the left attached to the tap with a brass 1/2 inch to hose connector. To get a seal between this and the steel tap thread I needed to get 3mm thick rubber washers and I added thread dope for good measure.
The silicone hose draws from a water carrier on the floor under the wooden worktop next to the sink. As it’s the low pressure side, it works without the complication of a jubilee clip to hold the hose in place. There’s a brass double-ended hose connector in the top of the carrier with a short length of silicone hose inside, running to the bottom of the carrier to get almost all the water out. This kind of system needs a water carrier with a cap that is big enough to get your hand in to fit the connector, the hose, and to remove it for cleaning.
With it all in place and the electrics wired into the 12V circuit, we have water! The new system is a definite improvement. The swivel tap reaches further into the sink which is better for hand washing too. The pump is very noisy for the few seconds it’s running, and its four litres per minute would be modest at home, but is plenty when you are bringing all the water onto site.