Water stored for years in water butts

Hi all,

On our plot, we have an opaque blue water barrel and black cylindrical water tank (not sure what it's actually called). They've both been full of water since we got the plot last summer, and presumably for some time before that as they weren't attached to a water collection system at the time and the plot hadn't been in use during 2019 before we took it on. I can't really see inside the blue barrel with any great clarity, but I get the impression their might be green algae or similar on the surface of the water. They are both quite full and the contain what I'm guessing is hundreds of liters of water.

I'm wondering if we should use the water in these old storage systems, try to empty them and clean them, or treat the water in some fashion. They have sunk down so that the taps are hard to access, but I can try to do so once I know what I'm looking for in the dispensed water.

Thanks!

Try getting a sample of the water from about 4ins below the surface you can do this by covering the end of a short length of water pipe with your thumb push it under the surface remove thumb for about 20 seconds recover and pull the hose out hold it over a clean container and allow the water to empty if it looks clean it should be OK to use if its, green should be OK to use outside in the open garden but not on pots if you are still unsure drain and wash out I would also avoid any contact with the water

I think I would try giving a single plant a nice soaking, as a little test. A bean, maybe. Give it a week and see if it likes it. If there's no ill effects I'd then go ahead and use the water over the whole plot. Waste not want not.

Thanks. Good, actionable ideas. I'll try to liberate some water next time I'm out at the plot.

I have numerous water buts dotted around the plot along with 2 galvanised troughs that collect water from 2 old pig shelters, a lot of them have green algae on them for much of the year. The water below seems fine as I use it throughout the year. I have just erected a new frame to take the large container I use, because it has a large surface area it tends to green up I think because it gets a lot of sunshine. I have taped some polythene to the poly tunnel and draped in the container to collect water from the roof and connected it to an irrigation system, all I need now is some rain.

There could be a small risk that legionella pneumophila bacteria has colonised the water, i would avoid spraying any of it.

There could be a small risk that legionella pneumophila bacteria has colonised the water, i would avoid spraying any of it.

This is just the kind of thing I worry about. Do you mean avoid spraying to avoid aerosolizing, or I should avoid applying it at all?

Legionella is only dangerous in in aerosol/atomised size droplets. Will be fineto water plants imo

If you are growing flowers as well as edibles why not try it on some of those first. I have water butts dotted around the garden which I use to water all but my veggies. This is run off from roofing. I have a separate butt full of intentional stinky juice I use to water my veg.