“Please conserve water!” (Why?)

As you turn your face upwards to the sky this autumn and feel the steady, blessed rain coming down, you might well wonder why there are signs around the island asking us to conserve water. Even after such a long dry summer, it seems we always have the wet winter waiting for us, and indeed the average rainfall here amounts to just under three feet (838 mm) annually. So where exactly does all that rain go, and why do Mayne Islanders need to be careful about water consumption?

Most island homes rely solely on groundwater provided by local water districts or private wells. As we explained in an earlier article, even though vast quantities of rain fall from the sky during cooler months, the health of our aquifers depends a lot on us. Many places in B.C. have reservoirs to provide citizens with tap water such as the huge lake in Sooke, which is operated by the Capital Regional District and supplies water to over 350,000 people in Greater Victoria. Here on Mayne there is no reservoir or any plan to build one. Average daily water consumption in the CRD is 260 litres (58 gallons) per person, and the 2016 census showed Mayne’s population to be around 1000 people. With the increase in year-round residents over the past few years, more groundwater will be used than when just one third of homes were occupied full time.

Every summer, there are wells here that run dry, or the water coming out of them becomes turbid and undrinkable. One densely populated district saw water usage double this summer and also experienced salt intrusion. You may have noticed the water tankers on the ferry who become the source of potable water under such stressful conditions. Continued clearing of building lots and reduction of the forest canopy reduces rainwater absorption into the ground and increases surface runoff and erosion. Rain diverted by hard surfaces picks up pollutants, debris and grit before it disappears via ditches and culverts into the ocean. Aquifers near the shoreline are becoming increasingly susceptible to saltwater intrusion because of rising sea levels. With the combination of climate change and the increase in population and demand for water on the island, it seems that serious problems with our aquifers are inevitable in the future, particularly in the more densely developed parts of the island.

raindrop on branch
Photo by Jeiline, Creative Commons

Short term solutions we can all do

Being resourceful islanders, there are specific actions we can take to avoid a water crisis. The first and easiest stage of conscientious water use includes things that everyone can do. It is important to turn off your water when leaving the island and regularly check the system for leaks. Install low-flush toilets, showers and washing machines, and turn off taps while washing up, brushing teeth etc. Toilets that run continuously due to faulty flappers and seals can waste gallons of potable water each day. To see if your toilet is leaking, put a few drops of food colouring in the tank and wait for 20 minutes. If the colour spreads into the toilet bowl, you have a leak. Following “waterwise” gardening techniques, and using only rainwater for cleaning decks, vehicles, driveways and paths is also essential to protect precious groundwater. If you enjoy gadgets, consider setting up a water meter on your well and challenge yourself to reduce your consumption. How low can you go? The water districts on Mayne use meters which allow them to monitor use per household and detect system leaks.

Innovative thinking for the long term

However, long term we are going to need to be innovative and make more drastic changes to how we use water in the Gulf Islands. When you consider the possibility of harvesting the abundance of rain that falls on us each year, the future of water conservation looks a lot more promising. Here on Mayne, we have a water catchment and storage deficit and therefore should take advantage of the clean naturally-distilled water supplied by the clouds every winter.  

Local architect Richard Iredale has designed several homes on Mayne that use rainwater as their only source of water, and there are now many houses that either use a combination of rain and groundwater or rely 100% on rain. For homes in rocky and shoreline locations, the cost of drilling a well and the potential salinity of the groundwater make rainwater the cheaper choice as well. All you need are a 3000 gallon (13,600 L) tank per person for indoor use, (more if you have a garden or orchard), a gutter screen or basket filter, a 5/20 micron filter and UV bulb steriliser, and a pump. In other words, the same mechanisms that are used in groundwater systems also apply to rainwater ones. One important consideration is your roof, however. Metal roofs are the only type that are suitable for providing potable water as treated shingles and asphalt contain toxic chemicals. According to the Premier Plastics website, from our 33″ (838mm) of annual rain, a 1000 sq ft (92.9 sq m) roof can harvest 13,000 gallons (59,100 L) of water in a year!

Long term residents Carol and Bernie Peets have been living only on rainwater for over 10 years, as the location of their home near the sea meant that the well was producing salty, unpalatable water. They have three tanks for their indoor use (two plastic and one concrete cistern), and an additional one that is not connected to the filtration system for their garden. They served me a glass of the most delicate-tasting water I have ever sipped. No sulphur smell or chlorine, just lovely pure water.

As our summer droughts continue and the island’s population increases, we all need to take whatever measures we can to protect our water. As the Mayne Island Integrated Water Society says on their website, “Without water, there will be no life. Without water, we cannot live. Without water, our land has little value.” So please, conserve water in whatever ways you can.

[Many thanks to Bill Warning, Richard Iredale, and Carol and Bernie Peets for their help in writing this article.]

For further information on Water Conservation and Rainwater Harvesting, please follow the links below:


Elsie Sands · November 2, 2021 at 6:28 pm

Thanks for this great article, Nancy. I appreciate your explanation of the problem and your many helpful suggestions about how to help.

Sheila Drew · November 5, 2021 at 8:45 am

Great article! So readable and informative! So encouraging, clear, and helpful on what can be done.

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