top of page

Flint and the Safe Drinking Water Act

The first question you may have asked yourself was, how can a public health emergency like Flint happen? Aren’t there laws in place to ensure that our drinking water is safe to drink?

The quick answer is: yes. What might be surprising is that we didn’t have a federal law guaranteeing the safety of drinking water quality across the United States until 1974. Below we explain and discuss the requirements of the Safe Drinking Water Act (“SDWA”), including:

  • what is the SDWA?

  • when is the Environmental Protection Agency ("EPA") required to regulate a contaminant, such as lead, in drinking water?

  • what do those the laws and implementing regulations looks like?

  • how are new contaminants added to the list?

  • what are the specific rules for preventing and monitoring lead in drinking water?


The SDWA is a federal law authorizing EPA to establish National Primary Drinking Water Regulations (“NPDWRs”) and National Secondary Drinking Water Regulations (“NSDWRs”). The NPDWRs establish mandatory, legally enforceable water quality standards (called MCLs). These standards are enacted to limit the presence of certain contaminants – such as lead, copper, arsenic – that can cause harm to human health. EPA also establishes non-mandatory standards intended to manage the aesthetic aspects to water, such as taste, odor, and sight. While not threatening to human health, drinking brown-colored water isn’t particularly appetizing.


Under the SDWA, only certain types of contaminants have to be regulated. The Environmental Protection Agency (“EPA”) is responsible for determining the maximum amount of a contaminant that is allowable in drinking water when:

- the contaminant may have an adverse effect on human health

- the contaminant is known to occur or there is a substantial likelihood that it will occur in public water systems with a frequency and at levels dangerous to human health; and

- regulation of the contaminant presents a meaningful opportunity for reducing risk to health.[i]


First, EPA must first set a Maximum Contaminant Level Goal (“MCLG”) for the contaminant. The MCLG is the level of contaminant at which there are no known or anticipated adverse effects on human health and which allows for an adequate margin of safety.[ii] This is the ideal level of protection designed to provide maximum protection to the population.

Second, after setting the MCLG, EPA must either set a Maximum Contaminant Level (“MCL”) or designate a treatment technique (“TT”). EPA is required to set the MCL–an amount of a contaminant measured in parts per billion–as close to the MCLG as is “feasible.” A feasible MCL is a limit that can be achieved using the best available technology while taking cost into consideration. Public water systems–or the water supply systems responsible for bringing drinking water to our tap–are required to monitor and meet the MCLs.[iii]

EPA may also designate TTs instead of MCLs when it is not economically or technologically feasible to ascertain a specific level of the contaminant. EPA must identify treatment techniques which prevent known or anticipated adverse effects on human health to the extent feasible.[iv]


No less than every six years EPA must review and revise existing MCLs and TTs.[v] Every five years, EPA must publish a list of contaminants not currently subject to any MCL which are known to or anticipated to occur in public water systems and may present a threat to public health. Should EPA choose not to regulate a contaminant, it may develop a public health advisory, a non-enforceable federal limit.[vi]


Exposure to lead has serious consequences, including damage to the brain, nervous system, kidneys, reproductive system and red blood systems. It is particularly toxic to children under the age of six. Therefore, EPA set the MCLG for lead at 0 milligrams per liter (mg/L).[vii] This means that no amount of lead in drinking water is safe for human health.[viii]

However, instead of setting an MCL, EPA established an “action level”. An action level is not an MCL. An action level represents the level of contamination that triggers a public water system’s obligation to adopt a TT. In the case of lead, if more than 10% of tap water samples collected from homes exceed the action level of 15ppb, public water systems must adopt certain TTs, such as installing corrosion control treatment, monitoring source water, replacing lead services lines, and/or undertaking a public education program.[ix] Large public water systems (i.e. those systems serving more than 50,000 people) must adopt a corrosion control treatment program if after 2 six-month periods of monitoring the lead actions levels are exceeded.[x]

EPA has decided to adopt an action level instead of an MCL for lead because of how lead contaminates drinking water and where in the distribution system lead can enter the water. Lead typically enters drinking water from the corrosion of pipes owned by individual customers rather than through pipes owned by the public water systems.[xi] Because MCLs are designed to measure the quality of the drinking water and the public water system’s success in reducing the presence of the contaminants, MCLs are not generally effective against lead contamination. An MCL measured where the water enters the home—as is standard practice—would not show how much lead is in the drinking water actually coming out of the taps, and an MCL measured at the tap holds the public water systems responsible for quality issues outside of their authority. Therefore, in cities where lead pipes are still present, EPA determined that requiring the application of a TT, specifically corrosion-control treatment which prevents corrosive water from leaching lead from lead pipes, best addresses the threat to drinking water and protects drinking water quality.[xii] In Flint many of the service lines–the pipes bringing water from the main line to the homes–are owned by the public water system and are lead pipes which are thought to have caused the presence of lead in drinking water.[xiii]


In our next blog we will discuss the application of the federal rules in Michigan and potential weaknesses in the law that frustrate the achievement of safe drinking water throughout the U.S.


[i] 42 USCS § 300g-1(b)(1)(A).

[ii] 42 USCS § 300g-1(b)(4)(A).

[iii] 42 USCS §300g-1(b)(4)(B)-(D), §300g-1(b)(5)-(6).

[iv] 42 USCS §300g-1(b)(7).

[v] 42 USCS §300g-1(b)(9).

[vi] 42 USCS §300-g(b)(1)(B)(i)(I).

[vii] In 1991, EPA added a new regulation for lead and copper. This regulation is referred to as the Lead and Copper Rule (“LCR”).

[viii] 40 CFR 141.51(b).

[ix] 40 CFR 141.80(c). 56 FR 26460 (June 7, 1991).

[x] 40 CFR 141.81(e), 40 CFR 141.2 (2016).

[xi] For a picture of a drinking water distribution system visit

[xii] American Water Works Ass'n v. EPA, 40 F.3d 1266 (1994).

[xiii] City of Flint, Quarter Water Quality Report, October 2015, available at

#Flint #DrinkingWater #SDWA

Featured Posts
Recent Posts
bottom of page