2025 Nelsen Corporation Catalog - Catalog - Page 423
National Primary Drinking Water Regulations 17
National Primary Drinking Water Regulations (NPDWRs or
primary standards) are legally enforceable standards that
apply to public drinking water systems. Primary standards
protect drinking water quality by limiting the levels of specific
contaminants that can adversely affect public health and are
known or anticipated to occur in drinking water. The following
tables divide these contaminants into Microorganisms,
Radio Nuclides, Inorganic Chemicals, Organic Chemical and
Disinfectant/ Disinfectant By-products.
For simplicity, WQA uses the term Point-Of-Use (POU)
when referring to both treatment at the tap and for whole
house treatment.
Except for instances of contamination through inhalation or
dermal adsorption, the WQA notes that in-home treatment of
drinking and cooking water only is often the most economical
and preferred method of choice for consumer protection from
these drinking water health contaminants. Of course, the
particular contaminant found in the water will determine the
appropriate treatment technique.
The recognized treatment methods listed here reflect the
fact that point-of-use systems on the market today may differ
widely in their effectiveness to treat any specific contaminant.
Also, many of the these can appear in a variety of forms (ionic
and/or organic). Examples include arsenic, lead, chromium
and mercury which may require different or multiple
treatment techniques. Anyone contemplating use of such
point-of-use equipment for a specific application or purpose
should make their selection only after careful investigation
and substantiation of the performance capabilities. As
part of the installation procedure, the performance of
the system should be verified through an appropriate
water analysis. In addition, the product water should be
monitored and appropriately serviced to ensure continued
satisfactory performance.
It is the general consensus of the manufacturers and
sellers of the point-of-use systems employing the listed
technologies that, if these systems are defect-free, properly
applied and installed and maintained strictly according to the
manufacturers’ installation and maintenance instructions, they
may be considered for use in meeting the requirements of the
National Primary Drinking Water Regulations (NPDWR).
Note: This document addresses the United States
Environmental Protection Agency National Primary
Drinking Water Regulations in effect at its time of
publication. These regulations are continually being
reviewed and updated at the federal level. Accordingly,
this list of recognized treatment technologies will be
reviewed and amended periodically.
EPA Primary (Health-Related) Microbial & Turbidity Contaminants
Contaminants
MCLG+
Turbidity
MCL+
Treatment Methods
0.5 to 1 NTU in 95%
of samples;
maximum of 5 NTU
under certain
circumstances
Coagulation/Filtration
Submicron Filtration
Reverse Osmosis
Sediment Reduction
Ultrafiltration
Distillation
Cartridge Filtration matched to turbidity particle size
Turbidity or sediment reduction to 1 NTU, then:
Coliform bacteria
zero
zero in 95% of
samples
Disinfection
Chlorination
Ozone
Ultraviolet Radiation
Iodine (Polyiodide
Resins)
Ultraviolet Radiation
Distillation
Submicron (absolute) Filtration (
