There are many reasons people around the globe choose to participate in rainwater harvesting. It could be to feel a sense of satisfaction and pride for doing their part to help the planet, a desire to save money on the monthly water bill, to reduce their dependence on the municipal supply, or simply because they lack other water sources.
Whatever the reason, it’s natural for those considering implementing a rainwater harvesting system to engage in a cost benefit analysis, though no price is too high to those residing in areas with limited water resources, since they’re dependent upon rainwater to continue living.
Yet let us consider a household blessed with an adequate water supply from the public utility, but is still planning to install a rainwater harvesting system. The financial outlay for the system will be weighed against the benefits of the system (such as reduced water utility bills).
A clear winner? Not so fast…
A quick check on utility water pricing reveals that the US has relatively low water pricing. According to a 2010 study conducted by the Low Impact Development Centre, the price of water in the US ranges between $0.70 and $4.00 per 1000 gallons with an average of $2.50. Considering a 3% year over year (YoY) rise in rates as projected by some public water suppliers, the benefits of installing a rainwater system might pale in comparison to the significantly lower cost of paying for centrally supplied water over a 25 to 30-year time horizon.
Conversely a 2010 article in the American Water Works Association Journal cites several examples of rapidly increasing water prices and the potential for a significant rise in rates of utility supplied water in the coming years. This can massively tilt the balance in favor of installing a rainwater harvesting system.
To corroborate this hypothesis, the US Environmental Protection Agency (EPA) is advocating true water pricing – pricing which accurately reflects the true cost of collection, treatment and distribution of high quality water – to encourage conservation.
An ideal strategy would provide the right balance of affordable water for basic and essential needs, and higher rates for non-essential uses like washing, landscaping, etc. This is established by having a tiered or block rate tariff system based on customer profile/ type. The first block would have the lowest unit price (cost per gallon) and would ideally provide enough water to meet the basic needs of that customer type. Subsequent blocks would have an increasing cost per gallon of water, motivating high volume users to look for alternative water sources to offset the higher block rates.
In addition to the economic aspect, there are hidden costs associated with utilizing water from a central source. One such cost is when water is extracted from a remote source. There is a significant energy consumption for the extraction, treatment and distribution of water. In the US, the water sector alone consumes 3% of the overall energy consumed. Decreasing water demand by 1 million gallons can reduce electricity use by nearly 1500 kilo watt hour, which results in reduced carbon emissions. Though this is not a tangible economic benefit for an individual household engaged in rainwater harvesting, at a macro city/ country level, conservation and reduced dependency on utility supplied water would result in significant economic and environmental benefits.
Rain Barrel Program at Arlington Eco fest. Image credit – Texas A&M AgriLife Extension Service
Credits and Incentives
Because of the significant impact heavy rainfall has on the downstream storm water management infrastructure, a number of cities in the US are encouraging property owners to practice on site storm water management (by retention of roof top runoff). This encouragement takes the form of credits or fee reductions against storm water utility fees. For example:
- Richmond, Virginia provides storm water fees reduction to the tune of 50% for property owners who have cisterns installed to capture their rooftop runoff. This in turn reduces their contribution to storm water runoff quantity.
- San Francisco encourages immediate use of the collected water in the barrel so as to optimize collection from subsequent rainfall.
- Los Angeles encourages the creation of rain gardens in residential properties to take in rainwater.
- Rhode Island extends an income tax credit of 10% of the cost of installing the cistern not exceeding $1000.00.
Texas has a comprehensive list of credits and regulations with respect to rainwater harvesting:
- Financial institutions are encouraged to provide loans for developments which use rainwater as the sole source of supply.
- A rainwater harvesting system is to be incorporated in the design of any new state building meeting certain specifications.
- Residential, commercial and industrial facilities are motivated to install rainwater harvesting systems through discounts and rebates for rain barrels/ water storage facilities.
So regardless of why people choose to harvest rainwater, it isn’t an understatement to say that it offers many benefits- environmental, economical, and emotional- and those benefits are sure to grow in the coming days.