Ask Pat: Grey Water

Lindsay asks—

Hi Pat,

Do the New Westminster city bylaws allow me to install a grey water system in my bathroom where I can redirect, filter and retain shower water? I live on a steep hill (like many other residents!) and I would like, with the aid of gravity and waste water, to grow my garden responsibly. Currently, we are using buckets. A filtration system would allow us to store the water when we produce more than we need, and a three way valve from the washroom would maximize our efficiency.

Thank you!

Some people probably read the above and cannot imagine why someone would want to keep the water coming out of their shower drain. However, re-use of “grey water” (waste water that has not come in contact with sewage) is pretty common around the world outside of North America.

I have a family member that lives on a Gulf Island where groundwater resources are scarce, and she lived for years off of rainwater collected from her roof. It doesn’t rain much on the Gulf Islands, so she relied on a large storage tank, and careful conservation of water. She also had a spectacular vegetable garden, maintained almost completely from grey water that she recycled the old-fashioned way: collecting it in buckets instead of letting it run down the drain.

This simple method relies on a few things: using the water pretty much when you produce it so no storage is necessary (giving no time for water to fester and pathogens to grow) and careful selection of soaps and detergents to assure you aren’t spreading too much sodium, sulphates, boron, or other things bad for soil structure onto your garden. As kitchen water is sometimes used, there is an extremely small but non-zero risk of food borne illness transmitting to your root vegetables, but good kitchen hygiene can make this risk vanishingly small.

The storage thing is probably your biggest issue. Just filtering the hair, lint, and other cooties out of the water will not stop collected greywater from getting septic very fast. Once you have warmed it, volatilized the chlorine out of it, and added a little organic matter, that water is going to get gross. If you wish to store it, you will need to filter then treat the water, with something like UV or ozone or you will quickly have a smelly putrid mess.

But your question was whether our Bylaws allow it, and I would say it depends on the Bylaw you read. The Plumbing Bylaw says:

No person shall cause, suffer or permit the disposal of sewage, human excrement, or liquid wastes, in any place or manner except through and by means of an approved plumbing system, conforming to the British  Columbia Plumbing Code and this bylaw…

Grey water would follow under the category of Liquid Waste, so if the BC Building Code allows your pipe system, the City would. There have been some recent changes to the BC Building Code that do allow for two-pipe systems and some recycling of non-potable water, but you are going to need to get a Building Code expert to answer any questions around that.

However, the City also has a Sewerage and Drainage Bylaw that says, amongst other things:

13. Every owner shall ensure that:
(a) all Sewerage originating from any building located on such property owner’s  property is connected to and discharged into the Municipal Sewerage System, when such a system is available to the property;

“Sewerage” is defined in the same Bylaw to include:

waterborne Waste from the preparation and consumption of food and drink, dishwashing, bathing, showering, and general household cleaning and laundry;

which leads me to conclude that the way you are currently collecting buckets of grey water and dumping them on your garden is illegal.

Worse, the same Bylaw also states:

14. Holding tanks are not allowed on any property within the area of the City that has been designated as the Metro Vancouver’s Regional Growth Strategy – Urban Containment Area, and the City will not permit a Service Connection to a property that contains a holding tank and owners must remove all such holding tanks.

This would probably be a more useful restriction if the bylaw defined “Holding Tank”, which it doesn’t, but I would assume that a tank to hold grey water or liquid waste would qualify (and I am suddenly concerned about the rain water collection tanks I purchased from the City).

This brings me to my easiest conclusion. I would suggest if you were getting into a storage-of-water-program for your garden to reduce water wastage, build a larger-capacity rainwater collection system instead, avoid all the trouble with putrefaction of organics in the grey water, and let your grey water go efficiently to the treatment plant.

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