How Does California Set a Drinking Water Standard?

Last week, I wrote about the process the U.S. Environmental Protection Agency (EPA) goes through to set a new drinking water standard.  This week, we’ll take a look at the process the State of California goes through to set a standard at their level.

As you no doubt remember, in addition to drinking water standards set by the EPA, each state can also set its own standards as long as they are at least as stringent as the EPA standards.  For example, states can decide to enforce the EPA's secondary drinking water standards.  California enforces several of these, including iron and manganese.  A state can also set a standard completely separate from the EPA.  California has chosen to do this in the case of perchlorate.  The EPA had previously declined to set a standard for perchlorate, although they are working on one now.  California, however, adopted a regulation that became effective in October 2007 that set an MCL for perchlorate at 6 ug/L.  The process for adoption of a standard in California is similar to the EPA's process, so we'll just take a quick look at that process in general.  

Once the state makes a determination that a contaminant should be considered for regulation, the Office of Environmental Health Hazard Assesment, or OEHHA, sets a public health goal (PHG). A PHG is the concentration of a drinking water contaminant that poses no significant health risk if consumed for a lifetime, based on current risk assessment principles, practices, and methods. OEHHA reviews all available published health risk data in making that determination.  Once the PHG is finalized, the Department of Public Health (DPH) must set a Maximum Contaminant Level (MCL) as close as possible to the PHG.  As part of that process, DPHs Drinking Water Program evaluates the technical and economic feasibility of regulating a chemical contaminant.  Technical feasibility includes an evaluation of commercial laboratories' ability to analyze for and detect the chemical in drinking water; the costs of monitoring; and the costs of treatment required to remove the contaminant.  Costs are required by law to be considered whenever MCLs are adopted. To determine technical and economic feasibility, CDPH selects possible draft MCL concentration or concentrations for evaluation.  They then evaluate the occurrence data; evaluate available analytical methods and estimate monitoring costs; estimate population exposures at the draft MCL concentration; identify best available technologies (BATs) for treatment; estimate treatment costs at the draft MCL concentration; and review the costs and associated health benefits (health risk reductions) that result from treatment at the draft MCL concentration.

Based on all of this, DPH proposes a draft MCL concentration.  The draft MCL then moves through the standard law making process, including public review and comment.  Once finalized, the regulation goes into effect 30 days later or at an agreed upon date.  Existing MCLs are reviewed by CDPH every 5 years to see if they should be changed, which usually means lowered to be closer to the PHG.

This process sounds very scientific and all, but unfortunately can be all too easily co-opted by political forces.  Hard to believe, I know.  A good example of that is the ongoing battle over a hexavalent chromium, or chrome 6, MCL.  This compound, which is highly toxic if inhaled at even very low levels; and also known to be quite toxic if ingested in very high concentrations; is embroiled in scientific controversy when it comes to its toxicity at the very low levels found in most drinking water.  There seems to be evidence that at these levels, there is very little risk.  Granted, that point can be and is being argued quite loudly by both sides of this issue.  It also would appear that DPH did not adequately take into account the costs of treatment in their health risk reduction calculations.  If the currently proposed MCL of 10 ug/L for chrome 6 becomes law, many millions of dollars will have to be spent on water treatment to provide minimal, if any meaningful health risk reduction for Californians.  And guess who will pay those millions of dollars?  The rate payers in the systems that require treatment, that’s who.  So why is the MCL being proposed at all?  Because of political pressures brought to bear after a great deal of publicity regarding chrome 6.  Not something you like to see happen in the regulatory compliance business, which should be science based.

With the proposed transfer of the Drinking Water Program in California from DPH to the State Water Resources Control Board (SWRCB), will this process change at all?  Yes it will, but I don’t think significantly.  The SWRCB Deputy Director would develop proposed MCLs that would then be considered by the full Board.  After public meetings and replying to public comments on the proposed regulation, the Board would act on it in a public meeting.  If approved, the regulation would then move through the regular law making procedure, being submitted to the Office of Administrative Law for review.  The question I have is will the SWRCB be more, less, or equally influenced by the types of political pressures we just talked about in regard to chrome 6?  I think we’re just going to have to wait and see on that one.

And that is how the State of California institutes drinking water regulations apart from the Federal process.  Other states have a similar process.  Let me know if you have any questions, comments on the process, or corrections to what I've presented here, and thanks for reading!