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Dear NEC,

I have noticed the foul condition of the Mad River. This is our drinking water. Does the local water district check for pesticide build up at the intake pumps? Will the rains (if they ever come) wash the filth from the weed grows into our home water taps? Where do birds get a drink? 

Thanks, Water Wary


Dear Water Wary,

According to the Humboldt Bay Municipal Water District (HBMWD), “Drinking water delivered by the District is drawn from wells below the bed of the Mad River northeast of Arcata. This water-bearing ground below the river is called an aquifer. These wells, called Ranney Wells, draw water from the sands and gravel of the aquifer at depths of 60 to 90 feet, thereby providing a natural filtration process. During the summer, this naturally filtered water is disinfected via chlorination and delivered to the District’s wholesale municipal and retail customers in the Humboldt Bay area. During the winter, it is further treated at a regional Turbidity Reduction Facility which reduces the occasional turbidity (cloudiness) in the District’s source water.”

John Friedenbach, General Manager of the Humboldt Bay Municipal Water District, says that the depth of these wells and the natural filtration process means that the water you eventually drink hasn’t come in contact with the foulness that you are observing on the surface of the river. “Blue green algae on the surface is not an issue for our drinking water because the depth from which the water is pumped,” he said.

As a stipulation of the Safe Drinking Water Act (SDWA), every municipal water district must provide a yearly Consumer Confidence Report (CCR). HBMWD’s can be found on its website at In addition to the tests listed on that report, HBMWD also follows the EPA’s Unregulated Contaminant Monitoring Rule (UCMR), which recommends that water districts test for certain “constituents of concern,” i.e. contaminants that are suspected to be in drinking water but do not have health-based standards set under the SDWA. The SDWA was first passed in 1974, so amendments have been made to account for contaminants that weren’t originally in the legislation, and results from UCMR tests can be used to influence which toxins are regulated. HBMWD most recently used UCMR4, which requires monitoring for 30 chemical contaminants between 2018 and 2020. UCMR4 tests for 10 cyanotoxins (the toxins produced by cyanobacteria, or blue-green algae), two metals (germanium and manganese), eight pesticides and one pesticide manufacturing byproduct (including chlorpyrifos), three brominated Haloacetic acid groups, three alcohols and three other semivolatile chemicals. According to Friedenbach, the District’s most recent UCMR4 results for pesticides (using EPA test 525.3, which tests for 125 semi-volatile chemicals) all came back “non-detect.” So, that water coming out of your tap has been tested for many pesticides before it reaches you.

But what about the birds? The water at the surface has not gone through a filtration process, natural or otherwise and there is no SDWA for animals. C.J. Ralph of the Redwood Region Audubon Society says, “Providing water is a great idea for several reasons.  For one, it brings in birds that normally don’t come to seed or nectar feeders.  Of course, replace the water daily to keep it fresh.  For the bath itself you can use a shallow saucer like those under a potted plant.  Put it a few feet away from nearby cover so that cats have a couple of bounds before they’re there.  Birds will use it any time of the year, even in winter, but especially in the summer. Even in the winter the birds will use it, especially if it’s away from where cats might lay in wait.  Active water dripping into the saucer really brings in birds. You can get a kit at some local stores or Google “bird bath dripper kit” for suggestions.”