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MASTER PLANNING AND TREATMENT PROCESS SELECTION 2.5

Rules that have been finalized provide two levels of standards to be regulated--primary
and secondary standards.
Primary Drinking Water Standards are health-related criteria that require mandatory
enforcement by the federal USEPA or by state primacy agencies. Existing primary stan-
dards, as established by rules currently in effect as of January 2003, are described in Table
2.1. It is noted that the table does not address all established standards, but rather those
affecting design of the principal physical elements of treatment discussed later in the text.
Secondary Drinking Water Standards include criteria that are intended for control of
aesthetic factors. Unlike primary standards, parameters developed as secondary standards
are established as guidelines that are strongly recommended, but not required to be en-
forced. Some of these may be enforced at the discretion of individual state primacy agen-
cies. Table 2.2 summarizes existing secondary regulations. While parameters governed
by secondary standards are not generally health-related, they can have a significant effect
on customer acceptance and can be a source of considerable customer complaint. Among
these are water color and tastes and odors in the drinking water. While the secondary stan-
dards are presently observed in drinking water treatment more by customer needs than by
regulatory control, future findings may result in a switch of some of these constituents to
primary listing.

Significant Future Drinking Water Regulations in Progress

At press time, a number of new regulations were under development in various stages
from proposed through final promulgation to anticipated effective dates (Table 2.3). The
salient features of the more significant of these are as follows, with the anticipated ef-
fective dates shown in parentheses:

• Long-Term 1 Enhanced Surface Water Treatment Rule (LT1ESWTR-2004)--same re-
quirements as Interim Enhanced Surface Water Treatment Rule extended to include
systems serving under 10,000 people.
• Radon Rule (2005)--a limit of 300 pCi/L radon content for systems with a groundwa-
ter supply--higher limit may prevail with state multimedia mitigation programs.
• Sulfate Rule (undecided)--still under USEPA consideration (may not be included in
list of contaminants).
• Stage 2 Disinfectants/Disinfection By-products Rule (Stage 2 D/DBPR-2005)--
compliance based on compliance running average at individual locations rather than
average of all locations.
• Long-Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR-2005) for all sur-
face water systems or groundwater under the influence--at promulgations (2004) re-
quires 2-year monitoring program of monthly samples for Cryptosporidium (systems
over 10,000 people) or I-year, biweekly E. coli samples (under 10,000). If results trig-
ger remediation, measures to attain up to 2.5-1og improvements may be selected from
"tool boxes or bins" that may include additional treatment such as ozone or UV or even
improved watershed protection programs, each measure having individual assigned log
values.
• Ground Water Rule (GWR-2005)--initially will require treatment technology based on
evaluation of sanitary survey conducted by primacy agencies. Depending on suscepti-
bility of individual sources, up to 4-log treatment inactivation of viruses may be
required.