Indoor Rainwater Uses


Next to outdoor uses, toilet flushing and laundering represent about 20-40% of water usage totaling 50,000 gallons annually for a family of four. In larger, multi-unit facilities such as university dorms, the savings is far more.  This water may require treatment as per local codes, such as sediment filtration and disinfection with UV light or chlorine for uses inside buildings.

The best time to install rainwater plumbing specifically for toilet flushing and laundry is when during construction or major remodeing since separate water lines are required. However, in some cases this may be able to be done in existing buildings as a retrofit.

Estimating the Costs and Benefits

ECOVIE estimates the costs and benefits of using rainwater indoors. Typically, we will consider indoor applications after looking at outdoor water demands. NOTE: This type of project can be attractive financially since usage is year around.


Combining rainwater harvesting with low flow fixtures

At Ecovie, we totally endorse and support the use of dual flush, low flow toilets and other fixtures inside a building.  in fact, the combination of using rainwater harvesting with low flow fixtures maximizes the amount of reduction in municipal water use and reduces the cost of a rainwater collection system.  This is particularly important in the restaurant and hotel industries.

Using Graywater for Further Water Usage Reduction

Another alternative to consider when looking for ways to conserve your water usage is the capture and reuse of water from HVAC condensate, showers, and laundry (gray water) for outdoor irrigation and indoor non-potable uses (toilets flushing).  Condensate recovery does not require the type of treatment that other forms of recycled water do.  In fact it can be treated the same way as rainwater.  Rainwater is really just a form of condensate itself!

ECOVIE would be delighted to install a graywater system to further increase your water self-sufficiency and cost savings.

OK, so rainwater and graywater make sense for indoor no-potable uses. Check out the next section to find out how rainwater harvesting can be better than city water for indoor potable uses!