Is tumble dryer water safe for fish?

June 16, 2011 12:56 PM

Is water from a condenser tumble dryer safe to use in a fish tank?

On my tumble dryer the instructions suggest the condensed water can be used for watering plants, filling a steam iron, or a car battery, but not for drinking. I would like to use this water for water changes in my amazon tropical freshwater fish tank, as I live in a hard water area, and believe the fish would do better with soft water. I have found conflicting advice elsewhere online, but can find no authoritative source to suggest that the water is anything other than distilled. Is it pure enough for fish?

posted by roofus to pets & animals (11 answers total)

I know a dryer is not a humidifier, but you may want to check out this thread.
posted by Specklet at 1:05 PM on June 16, 2011

Don't do this. It is not impossible that some soap/softener/clothes dye/other chemical stuff might leave behind some volatile residue that will end up in the condenser water and will not sit well with your fish. Chances are this won't happen, but it's practicaly impossible to test for this kind of scenario with every brand of soap or whatever. It's obviously a conservative approach, but I wouldn't risk poisoning the fishies for the marginal benefit of free softer water.
posted by Dr Dracator at 1:06 PM on June 16, 2011 [1 favorite]

NO. This is condensate full of detergent and fabric softener remnants. NO.
posted by likeso at 1:08 PM on June 16, 2011 [1 favorite]

(on preview, what Dr Dracator said)
posted by likeso at 1:09 PM on June 16, 2011

Considering that water potable for humans can't be used for fish without some treatment, the answer has to be no.
posted by StickyCarpet at 1:14 PM on June 16, 2011

I would guess that it is only suitable for plant watering because the dirt will act as a filter for most of the remains. I would think this water qualifies as relatively good grey water. NOT water for consumption.
posted by edgeways at 2:15 PM on June 16, 2011

Water from your laundry is not distilled. Why would you think that? It has all sorts of debris and detergent in it...
posted by dfriedman at 2:19 PM on June 16, 2011

Do not use in your fish tank! Fish tanks need their water carefully monitored, and it starts with distilled.
posted by radioamy at 2:21 PM on June 16, 2011

FWIW, Distilled water isn't good for fish either. They usually need some sort of substance for osmotic balance. On top of that, distilled water often picks up the metal it was condensed on. RO water reconstituted for your fishes specific needs is much better.
posted by [insert clever name here] at 3:31 PM on June 16, 2011

Would you drink it? I know I wouldn't. And I certainly would not give it to my fish to swim around in.

This reminds of the time my neighbor took old gas from a chainsaw (two stroke, oil and gas mix) and put it in his new car.

That, like this is a bad idea from the giddyup. He ended up spending a lot to repair his fuel injection system. You'll won't spend a lot of money, but your fish will most likely become sick and perhaps die. Bad outcomes all 'round.
posted by chosemerveilleux at 2:51 AM on June 17, 2011

dfriedman: Water from a condenser tumble dryer *has* been distilled.

Of course the problem is that the surfaces the water condenses on are not necessarily themselves clean & neither are the pipes or tank in which the water collects, nor are they designed for this use: I doubt any PVC pipes or plastic tanks will be food safe for instance, so plasticisers may leach into the water, as will lead from soldered joints etc etc.

Water from a condenser tumble dryer *could* be equivalent to distilled water, but only if the dryer was designed appropriately & I doubt any are.
posted by pharm at 3:53 AM on June 17, 2011