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What Can You Do With Rainwater?

Even if spring officially just hit the calendar, the weather has definitely been spring-like for most of the month. One of the characteristics of spring is the rains, which can sometimes cause flooding in areas that aren’t equipped to deal with a large influx of water. Here in Boston, sewers designed especially for rainwater can collect runoff and return it to the Bay. But lately, everyone from the engineers to the environmentalists have expressed concern that on one hand, not enough rainwater is being returned to the ground to replenish the local aquifers, and on the other hand, the rainwater runoff collects industrial contaminants (like motor oil and fertilizers) before it hits the storm sewers and results in contamination of the Bay.

So besides shunting it down the storm sewers, what exactly can you do with rainwater?

As-is, rainwater isn’t considered potable. It’s not clean enough to drink and may contain (or collect) biological and chemical contaminants that make a person sick, either immediately or over the long term. That doesn’t mean you can’t do anything with rainwater, though!

Some homeowners have installed rainwater collection systems to “harvest” rainwater and use it for landscape watering and gardening. Used this way, rainwater is actually returned to the natural aquifers, just like nature intended. Rainwater collection systems can be as simple as rain barrels that hold 50-75 gallons of runoff from the home’s roof, or they can be somewhat more complicated, and include cistern water storage and gray water collection. In this setup, homeowners install a separate plumbing system that can collect and distribute the non-potable water to gardens and lawns.

Rainwater toilets are also gaining traction among the environmentally conscious, and have caught the attention of the City of Portland, OR. Toilets use potable water – the same water that comes out of your tap. There’s no need for toilet water to be drinkable (except maybe if you’re thinking about the dog), but attaching the toilet to the municipal water supply is the easiest way to ensure that you have enough water to flush the toilet. Therefore, the overwhelming majority of toilets use ultra-purified water.

A rainwater toilet uses collected rainwater to provide the flush. The toilet fixture is no different than what homeowners have in place now. Depending upon local codes and whether the toilet is being used in a residence or in a commercial building, it may not be sufficient just to put untreated rainwater in the toilet.

A rainwater flush toilet must be plumbed separately from the municipal water supply, and once the toilet is converted to use non-potable water, you can’t just reconnect it to the municipal supply. (You’d need to replumb with fresh pipes if you wanted to convert back.) For commercial applications, the rainwater must also be treated locally with chlorine and/or UV light, and special filters may be required to block organic debris from entering the system.

The immediate benefit of a rainwater toilet (or other rainwater collection system) is that it reduces the use of potable water for applications that don’t require super-pure water. On a large scale, this would reduce the demand for treated water.

Rainwater collection systems are relatively inexpensive to install and depending upon the size and type of the system, can reliably collect between 10,000 and 30,000 gallons of water per year.

If you’d like more information about rainwater collection systems or plumbing for non-potable water delivery, contact us at Boston Standard Plumbing & Heating at (617) 288-2911. We’ll be happy to provide a consultation.

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