I thought I would relate some information regarding rainwater collection for homeowners from my own experiences.
Assuming one doesn't have neighborhood residential restrictions for setting up some cisterns to collect rainwater off one's roof, then consider the following:
Each 1,550 gallon high-density polyethylene (HDPE) tank cost me about $439 from a "local" vendor--about 60 miles away. I bought three tanks. (I'm about to invest in three more 1,550 gallon tanks this year.) Shipping costs was about $120. The PVC pipes and fittings were about $200. The ballast pump was about $700. The $60 filter assembly included a 5 micron sediment filter and a 3 micron carbon filter and two pressure guages. The ultraviolet lamp (see http://www.ultraviolet.com
)was about $700. Rain gutters should be considered part of the cost of a rainwater collection system, but rain gutters aren't always used for collecting rainwater, since people put them on houses anyway for some reason.
I spent about $450 for rain gutters so I will include that cost here in this analysis.
Total investment: Approximately $3550. I spread this out over two years.
One cannot plumb a rainwater (nor a wellwater system for that matter) to any city service public water line-- "T'd" to the house-- unless you get a special permit (more $$$) which requires additional equipment such as back flow preventors, and the additional equipment must be installed by a certified plumber (more $$$) and inspected annually (more $$$). Of course, one may not want to pay such permitting fees and annual inspection fees every year. Forget that. A stand-alone rainwater system is less expensive than to pay for annual permits and inspections.
Additional ongoing maintenance costs include new filters after about two months or after filtering about 5,000 gallons of water. Home Depot sells the twin filter pack for $45. The frequency of replacing filters can vary, depending on how clean your rainwater is coming off the roof and how much water one uses. Leaves from roof-overhanging trees are not good for rainwater collection systems. Screens in the gutter downspouts work pretty well for large debris, and there are a couple of other plumbing tricks that remove solids that I won't detail here, but will prolong the life of the micron filters.
As far as rainwater saving energy, this could be debated. I now use more electricity per month at my house for the UV lamp and the pump. The UV lamp I have draws 36 watts, 24/7. The pump comes on everytime you turn on the water. I estimate the rainwater system uses about 30 additional kilowatt-hrs per month, about $3/mo. at my electric rate. I wonder how much power (or other embedded costs) I save the city water company. ???
Since I don't have enough storage capacity yet to last me through the dry summer season, I still am paying the city water company their $25 /mo. minimum fee to maintain their service if needed. Once I get more capacity, I can quit the city water service and then the payback begins...
The rain here in Central Texas is only slightly acidic, about pH 6.8. There is no limestone (calcium carbonate) in the rainwater compared to the city water. The city water ruined both toilets after 30 years from lime buildup. The new toilets should last forever with soft rainwater. Likewise for shower heads, faucets, hot water heaters, etc.
The dishes come out spotless.
The rainwater does not leave lime in my solar water still.
Clothes are cleaner.
There's no arsenic or lead in rainwater.
for more information.
The edit corrected the price per 1,550 gallon tank (at that time of purchase) and the total estimate.