12 May 2008


Anonymous asks me to comment on:
Greywater (methods, options, funding, laws)

Impacts of funding for small stormwater catchment versus upgrading city-wide systems ie would rain gardens make a realistic impact if funded and supported?

city-wide drug test by testing the effluent (research up in seattle or portland I think)
Lots of interesting topics here. Let me begin by linking to earlier posts on graywater, the legality of cachements and drugs in water.

Gray-water* (alt. grey-water -- I can't spell) is the runoff from kitchens, showers, etc. Some people want to re-use that water in their gardens so as reduce their use of fresh/clean tapwater. I am all in favor of the idea, but others are not. A public-health worker told me that graywater can contain fecal matter and other nasties that wash off your body and/or hands in the shower or sink. I tend to think that these fears are overblown. Those impurities are no doubt in the water (and detectable in tests), but they are probably "familiar" impurities that people are not worried about. Just as you may reuse the same cup or bottle many times between washings, many people are not upset about walking on lawns (or eating food) that is irrigated with runoff from their own households. OTOH, industrial-level runoff (or worse -- sewage-spreading), can spread heavy metals, hormones (see drugs in water), etc. from people that you are not happy to share germs with. The difference is not just an irrational taboo -- we are immune (or acclimated) to our own germs but do not play well with the germs of others. (Do you want to wipe your nose with someone else's handkerchief?)

Second, should cities spend more money on local cachement systems and less money on city-wide systems? I think yes, if only because one size does not fit all (in runoff and many other systems). Perhaps a hilly area produces more runoff than a flat area and should have more cachement infrastructure in the area. The way to reconcile this idea with political districts is by allocating a fixed $x to every area and then let them spend that money to maximize local conservation according to the local geography. (Alternative -- allocate $x/unit conserved.) Note that I am not favoring rain gardens over some other "technology" -- there is no best solution for all places.

Third, city-wide drug tests are an interesting idea. Besides their interest to sociologists (i.e., how drugged-up is a city?), there is little benefit in using them for policy. That's not to say that politicians wouldn't like to use them for policy (punish Seattle for pot-smokers but ignore sex hormones in San Francisco?), but I think that they are a political minefield. (A lot of drug abuse involves prescription drugs, and many interest groups like it that way.)

Bottom Lines: Public authorities should make it easier (permits, etc.) for people to install domestic graywater systems. Run-off programs should be centrally-funded and locally managed. Testing for drugs in the water is fun, but useless. Address the supply and demand for drugs instead.

* Not to be confused with black-water (sewage), blue-water (navies), white-water (rafting or Clintonian scandals), Gold-water (politicians), etc...

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