Water Quality and Health (Yang) (3/18)

Wisconsin's main sources of drinking water

In Wisconsin, we use surface water/groundwater as our main source of drinking water.

Fraction of Wisconsinites using surface water

⅓ of Wisconsinites use surface water as their main drinking source.

Wisconsin's main surface water sources

Lake Superior, Lake Winnebago, and Lake Michigan.

Fraction of Wisconsinites using groundwater

⅔ of Wisconsinites use groundwater as their main drinking source.

How Wisconsinites obtain drinking water

From a private well or a public water system.

Percentage of Wisconsinites using public water systems

70% of Wisconsinites get their drinking water from a public water system.

Law protecting public drinking water

The Safe Drinking Water Act of 1974.

Event spurring national environmental regulations pre-1974

The Cuyahoga River fire in 1969 was the impetuous to national interest in environmental regulations.

Safe Drinking Water Act of 1974 mandates

-Defines public drinking water systems.

-Mandates EPA standards for health-concerning substances.

-Requires monitoring and action for high contaminants.

Types of public water systems

Municipal, other than municipal, non-transient non-community, transient non-community.

Community vs. non-community water systems

Community: Municipal/other than municipal (serve where people live).

Non-community: Non-transient/transient (serve where people work, learn, pay).

Number of public water systems in Wisconsin

Wisconsin has more than 11,000 public water systems.

What drinking water standards regulate

They limit allowable substance levels in drinking water.

Number of substances with Wisconsin MCLs

Wisconsin has MCLs for over 90 substances (organic chemicals, radionuclides, inorganic chemicals, microbes, disinfectants, disinfection byproducts).

Requirements for public water systems

Collect samples and report results to the state.

Wisconsin's 2022 public water compliance rate

99% of systems met all drinking water standards.

Systems with the most MCL violations

Transient non-community systems, followed by municipal systems.

Systems with the highest bacterial MCL violations

Transient non-community systems.

Systems with the highest arsenic MCL violations

Non-transient non-community systems.

Systems with the highest nitrate MCL violations

Transient non-community systems.

Causes of remaining violations

Radionuclides, disinfection byproducts, benzene, phthalate, tetrachloroethylene.

Steps after MCL violations

Issue a public notice, then reduce contaminant levels.

Why establishing new standards is slow

The process can take a long time.

EPA's address of PFAS

-Added PFOA/PFOS to the third CCL.

-Included in unregulated contaminant monitoring.

-Established health advisories and draft/final MCLs (April 2024).

Duration of PFAS regulation process

Over 17 years.

Fraction of Wisconsinites using groundwater

⅔ of Wisconsinites.

Wisconsin's groundwater standards

Enforcement standard and preventative action limit.

Delays in groundwater standard adoption

Adoption into rule can take years or be delayed completely.

Summary of Wisconsin's drinking water

-70% use public systems regulated by the Safe Drinking Water Act.

-Most systems provide high quality water, but challenges include slow federal/state standard updates.