Garden Hose Chlorine Filter?

I've been doing some research into proper composting procedures and stumbled onto the worry that municipal water that is treated with chlorine added to compost or garden might be detrimental to the micro-biome.

While I am working on setting up my rain collection system, do you think it might be worth it to get my hands on a chlorine specific filter if it is not cost prohibitive?

Perhaps I am overly worried and should continue doing what I'm doing?

What are your thoughts?

My experience with chlorine is from maintaining my kids pool. For chlorine to be biologically active to sterilise water it needs to be at a high part-per-million concentration, and in the ideal pH zone. If you pool gets an algal bloom you need to boost the chlorine levels really high to kill it off - far higher than would ever be found in drinking water. Even then it needs to be sustained at that level for an extended period and is very quickly used up/evaporated away if the levels are not topped up.  Even a small amount of "dirt" in a pool (biological matter that can be chemically broken down by free chlorine) will very rapidly use up the chlorine in a pool.

I'm no expert on how this transfers to a compost heap, but given that the heap is essentially all biological matter an absolutely minute proportion of it will be broken down before the chlorine is all used up/rendered inert.

Bottom line - I would expect it to have no impact on your compost heap, beyond that dumping a large quantity of cold water would be expected to have anyway.

Michael,

Thank you for that explanation, the pool-based logic with concentration makes sense! I'm fortunate in the sense that our local water is 'minimally' treated but has to meet regulation standards but it is rare to detect the chlorine when you get it out of the tap.

I haven't seen any harm so far so I'm going to keep on trucking for my home.

Hi Timothy,
I don't like having chlorine in the water, and I think even small amounts over time could cause some biological disruption, both in our stomachs and in the compost pile. I don't think it would stop the composting, but depending on the amount, it might slow it down.

All the filters I have seen for chlorine are expensive and/or take a long time. Here are a couple other possibilities to help.

If it was me, and I had no other choice, I think I would just fill up a 5-gallon bucket ahead of time and let it sit for at least 5 days, and then use it. At that point, there should be none or almost none left. If you want it done faster...

1. Boiling - will help off-gas the chlorine more quickly.
2. Aerating - will help get rid of it faster.
3. Vitamin C - This one was new to me, but apparently certain forms of vitamin c can neutralize chlorine. The downside is you have to know how much chlorine is in the water, to put in the right amount of Vitamin C.

I don't know anything about the effect of chlorine on composting, but it's common for people to worry about using chlorinated water for briney fermentation and all the evidence I have is that it slows ferments down either not at all or an imperceptible amount without rigorous study. I favor spring and well water when I'm putting my ferments up, but when I lived in town, I used tap water regularly and it worked just fine. So this doesn't mean for sure that isn't disruptive to the compost pile, but it's some evidence in that direction.

Biochar, especially when made at higher temperature ranges (above 450 C), adsorbs chlorine very effectively. Activated carbon water filters for home use have been around for decades. Same principle. The engineering part is to design a simple chamber that holds a load of biochar, withstands mains pressure, and can be emptied and refilled easily.

Filling a tank or IBC tote and letting it stand for a day or two to offgas will also do the trick. But then you need to move the water...small pump, perhaps?

Christopher Weeks wrote:I don't know anything about the effect of chlorine on composting, but it's common for people to worry about using chlorinated water for briney fermentation and all the evidence I have is that it slows ferments down either not at all or an imperceptible amount without rigorous study. I favor spring and well water when I'm putting my ferments up, but when I lived in town, I used tap water regularly and it worked just fine. So this doesn't mean for sure that isn't disruptive to the compost pile, but it's some evidence in that direction.

I think a key difference is that most ferments are starting from tiny amounts of live yeasts - either wild strains, or deliberately introduced. Such cultures are very fragile until the number of yeast cells multiplies to a significant degree. I know my dad won't mix tap water with his dried live yeast powder when baking without letting it sit for a bit to evaporate any chlorine... but he hasn't had any trouble with his sourdough started mixes, where the number of actively breeding yeasts is huge.