Using Dirty Water On Plants

We don’t have a dishwasher. All our washing up is done by hand. There’s not much of it because we are partial to Marks & Spencer ready meals.

To each bowl of water we add a squirt of washing-up liquid, the ingredients of which are given as:

Anionic Surfactants (15-30%)
Nonionic Surfactants ((5-15%)

Given normal use of washing-up liquid, will using this dirty water on plants cause growth problems? Our plants don’t seem to be flourishing as much this year as last.

A small amount of detergent can be beneficial in that it can break surface tension and help plants absorb water, but it may be accumulating (especially in house plants) to a level that is now becoming toxic. I wouldn’t use it on a regular basis.

It should be OK on plants in the garden, but I wouldn’t use it on house plants, as it will build up in the soil.

On the bright side, radio DJs occasionally run contests for “Who’s the cheapest cheapskate” and get the sort of people who unroll two-ply toilet papaer to make two rolls of one-ply.

I’d think you stand a good chance of winning some cash in such a contest.



My father used to store the water used by the washing machine and use it to water his lawn. Not only did it not harm the plants, it seemed to dissuade the bugs as well.

I saw the use of sudsie water on gardens mostly 30 years ago, and the use after many times resulted in plants that didn’t do as well as ones it was not used to water. A layer of what looked like lard eventualy built up in the soil . It may be better to dump near a plant once or twice, during a dry spell, but I wouldn’t put it in the same place time after time. Some homes had a couple almost dead plant by the kitchen doors, and chances were that a person kept pooring the dish water there. I wouldn’t use it at all if possible. I do use a bucket of water to rinse in outside to keep from cloging drains and wasting water. The next time I water it goes on the plants, but it doesn’t have soap and food remains in it.

I do that at work, but just because the work toilet paper is so crappy (no pun intended.) It’s that rough, thick, institutional stuff that feels basically like office paper - except for whatever reason it’s two-ply. Trying to crinkle up two sheets of office paper instead of one makes doing your business even harder.

Here is a good article on the safe usage of Household Gray Water -

You know that the toilet paper is really bad, when it gives you paper cuts. :eek:


I appreciate your comment but I am talking about water, not toilet rolls.

Water is a no longer an infinite resource in the UK. Usage restrictions apply in my area in the shape of hosepipe bans. Other localities are subject to drought orders. The public is encouraged to save water in any way possible and many people use dirty water on their gardens. Some households have installed pipes to collect bathwater and store it for this purpose. I recall reading that the design of some new houses will incorporate various means of draining and storing dirty water.

I don’t consider the issue to be cash related. I find it extremely annoying that Thames Water (my supplier) wastes over 900 million litres of water per day through leaking pipes, but it costs very little in personal effort to re-use water in this way.

Furthermore, horror of horrors, I don’t always flush the lavatory after taking a piss. I’m usually quite fastidious but now I flush it when it is necessary to do so. I’ll spell it out if you like.

It’s a matter of balance. I don’t wear a still suit but equally I don’t wish to be profligate. Maybe you don’t have a problem with a lack of rainfall where you live.

I would recommend catching rain water if possible as a supliment. Use of mulch and drip irrigation helps reduce water usage alot, as does intensive gardening of plant beds. You plant with optimal spacing and leave no open areas, weeds and water use are both reduced. My aunt used a couple hundred foot of hose to water a large area from washing clothes. Moving the hose every day allowed for the disapation of toxins over a large area planted with hardy plants., and didn’t deter plant growth.

On the other hand, dirty water from your fish tank is fantastic for plants. Even though I’m a houseplant’s worst mother ever, most of mine thrive because when I do water them they get the fish-poopy water.

I don’t know the details of your soap ingredients and their affects on the plants, but one thing to be aware of is that salt is very bad for plants - and most foods use salt in some fashion. Almost all spice mixes have tons of salt, as well as a lot of condiments.

Also, as noted previously, grease and animal fats will become rancid AND attract unwanted animals.

I like the tip about aquarium water… I’ll have to start doing that.

I removed a gallon at a time from my aquarium, for the house plants. I was a well balanced tank, and the fresh gallon of water probably helped.

Thank you for the information.

To clear up one point, if I have just washed a roasting dish or something else coated in grease or animal fats the water is discarded in the normal way.

If it’s yellow,
let it mellow;
if it’s brown,
flush it down.

I like the idea about using it to flush your toilet; it was going to wind up in the same place anyway!

Newsprit paper will beat office paper 6 ways to Sunday.
Also is reminiscient of the out of date Sear and Roebuck catalogs that hung by a thick string in old time out houses.
AKA “The Little Brown Shack Out Back”
For for a real ‘treat’ ty a white corn cob, sans the corn kernels of coures, or a red cob if you are feeling really ‘tough.’

Couldn’t find James Whitcomb Rilery’s poem “The Old Outhouse” for all of you to enjoy.

You ought to be doing regular water changes anyway, not just when you think about the plants, FYI. :wink: