Cleaning a water tank, 101

I was mentally preparing for it for a while now, it was high time to thoroughly clean out my water tank. This kind of chore is not particularly the kind of thing I look forward to. I was dreading the whole ordeal. Every now and then I take a look inside my tank to see how much water is left. We haven’t had much rain lately, and I really needed to ration my water. About 10 centimetres of water was all that was left last time I checked and there was a fine layer of sediment at the bottom. Some sort of black stuff, I think it might be soot from the chimney that had fallen on my roof and which the rain washed away and into my tank. My DIY water filter is functioning well enough, but these really small particles still manage to get through.  There was also a little bit of biofilm on the sides of the tank and on the water hose that’s attached to my water pump. In any case, it is a good idea to empty and clean out your water tank at least once a year I reckon. Time to get to work!

But how do you go about a task like that? It seemed sensible to postpone this chore until the right moment, which would be right before it would rain for a couple of days. This week the weather forecast showed that we would be having some very warm days, followed by at least two days of heavy rain. Ideal weather! I asked around what kind of cleaner I could best use for a job like this, someone mentioned citronella. To be sure, I also asked advice from Boy from fablab de Kaasfabriek. He designed and created my filter and knows a lot about the subject of water filtering. He told me Citronella was a bad idea, I would taste and smell that in the water for months after cleaning the tank. Boy advised me to use sodium hypochlorite (bleach). It is chlorine, but without the perfume. It is used in swimming pools and to clean water tanks. I didn’t know that either to be honest, but now you and I both do. :)

Okay, let’s find this stuff. That proved to be not so easy. When you order it online you have to come pick it up yourself; it is not allowed to be sent by courier service. I was told that the stuff sometimes gets used for the production of explosives. Oh sure, I have a DIY explosives lab in the cellar beneath my Tiny House, didn’t you know? Hahaha! But I did find it at last, and not that far from home either. Welkoop, they have everything! Only…they had but one package size, and that was a jerrycan of 20 litres. I had no clue how much I needed and there weren’t any other options, so I bought one of the heavy jerrycans and took it home with me. I even had to provide my ID which they photocopied before I got to leave with the product. The warnings on the label worried me a bit, this stuff is aggressive! I double-checked with Boy: ‘Are you sure I can safely use this? Is it bad if some of it gets into the soil? How much do I need to use?’

Boy was able to set my mind at ease: I needed to dilute it so much that the end product was not dangerous, it would be common domestic use. I only needed a thimble-full! Well isn’t that great, there I was with a jerrycan of 20 litres of the stuff. Okay. Wednesday morning, wearing some old clothes, glasses on for safety, getting to business like a pro. Raymond of the Urban Earthship helped me out with removing the lid of the wooden box my water tank is in, and with getting the lid of the jerrycan of sodium hypochlorite off (it was stuck like it was glued tight). I took the filter out of the tank and poured about 20 millilitres of the sodium hypochlorite in the remaining water in the tank. I was planning to crawl into the tank myself, but one look at the opening made me realise that I couldn’t fit through it at all, haha! And either way, Boy had advised me against crawling in. So I bought a new broom to scrub the tank with, which worked out fine. Now I had to let it soak for 24 hours, to give it enough time to properly do its work. The waiting started, and every now and then I used the broom to make the sides of the tank wet again. I also rinsed the filter components, first with water in the garden and when the worst of the filth was rinsed out, I used the kitchen sink in the Gasfabriek to rinse some more with clean water. It’s so convenient that I have neighbours that I can turn to when I am in need of a water connection every now and then!

And then wait some more, and climb on top of the tank to swipe the broom through it again, and wait some more…

This morning I woke up to the sound of rain on the roof, at about 7 AM. ‘All right, I’ve waited long enough!’ I thought, ‘I need to catch that rain!’ I got dressed real quickly and scrubbed the tank one final time with the broom. I drained the tank, rinsed it with clean water, drained it again and … it was clean! Woohoo I did it!! I put the filter back in its position, connected the drain and sat down on my porch beneath my little awning. Proud of myself and happy with the rain!

Now, I still have to deal with this huge jerrycan of sodium hypochlorite. It becomes a lot less powerful after a year and there are not that many off-grid Tiny House people in the Netherlands yet who I might be able to give it to. Perhaps the people on the farm where Monique is camping can use it? I’m sure I will find someone that can. I hope we’ll get lots of rain now; I could use a nice shower after the warm days and yesterday’s activities!

Today my Berkey Water Filter was also delivered. With this beautiful Travel Berkey I can finally filter my rainwater so I can drink it. No more hauling heavy jerrycans, hurray! I’m going to test it well and then write a review about it here.

Water…we take it for granted so often here in the Netherlands, but for most of the world it isn’t all that normal to have clean drinking water at your disposal. Living in an off-grid Tiny House makes you more conscious of that, which isn’t a bad thing if you ask me. Sure, you have to adapt your usage to what nature offers you, but in the Netherlands there is always a back-up plan at hand. I’m doing fine this way. My water system is getting there. It is a matter of pioneering, but when it works, you’re set. No more bills from the water company! :)