Turning river water into drinking water

We do have a water supply to the finca, but it’s river water for irrigation use. It would be an immense cost, and a right pain, to use bottled water for drinking, so we set about making this dodgy water fit to drink.

So this is where our water supply comes onto our land, and we have a sediment filter – which we replaced with a whole new part when we moved in. When we purchased the finca, this was the only filter on the property – the internal filter had been changed and was the wrong size for the housing, so didn’t really do anything. The shower cubicle in the bathroom was testament to this – there was no saving it, we had to rip it out – absolutely brown and disgusting! The boiler was also knackered from having such dirty water being dragged through it. There is a pressure meter here so we can see what pressure the water is at – we average 9.5 bar!

Off to the right in the picture is one of the irrigation pipes with a tap to turn it on and off – there’s another out to the left too which is just out of shot. So the water for irrigation goes through just this one filter. We rinse this filter at least once a week.

The next step is a pressure regulator – allowing water to hit the house at 9.5 bar would be damaging to pipes, taps and the water filter fitted inside, so this allows us to regulate the pressure at just over 3 bar into the house:

Then we have two further filters on the pipe before the water enters the house:

We typically have a 20 micron and a 10 micron filter in these – and you can see how effective they are – they start out white! We change / clean these every 2-3 weeks typically.

So this grade of water, having gone through 3 filters, is what we use for washing etc – under test it comes out at about 180 parts per million. This is the water comes out of the kitchen and bathroom taps and the shower.

Then the final stage is the 5 stage reverse osmosis filter inside the house:

This filtered water then has its own holding tank in the same cupboard that holds about 9 litres and a separate tap. As you use the water the system bursts into life and replenishes the tank. We chose the non electric version without a pump as we only have solar power – the water comes out of the tap fairly gently but it’s fine – we’re not in a hurry! So by the time we drink the water it’s been through 8 filters!

We test the water regularly using a kit that cost just €20. There’s two parts to the test – the parts per million solids and the PH.

So what are safe levels of solids in water – in the UK its recommended no more than 200 parts per million, whilst in America, the standard is 100 ppm. We’ve set our own standard of 50 as the point where we’ll change the cartridges in the reverse osmosis system, just to be sure – you know what I’m like about having clean water!

Our filtered drinking water is currently at 32 ppm, so we’re all good at the moment. UK tap water is generally over 80 and under 200!

The instructions with the reverse osmosis system says to change 4 of the filters annually, and the last one is supposed to last about 5 years. But we’re very conscious that due to the nature of the water we get, the filters are likely to last less time than that – regular testing means we can spot quickly when we get to 50 ppm and change the filters. It worried both of us that one of these filters could fail and there’s no indicator to tell you that – if you’re filtering water that’s safe to begin with then it’s not a big deal, but in our case that could be a disaster and make us very unwell.

It took a couple of weeks, a little bit of engineering and quite a lot of swearing, but Rog got there with this system! All the bits we had to buy came in at under €200 and our annual costs for replacement filters will be about €100 which is a lot more economical than buying bottled water.

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