Multiple studies, including a 2018 study published in the Proceedings of the National Academy of Sciences (PNAS) that reviewed EPA data from 1982-2015, show that water companies have a stronger record of delivering high-quality water that meets or exceeds federal standards than their municipal counterparts. This 2018 study confirmed previous ones, including research out of Georgetown University and Texas A&M, that concluded that privately-owned water systems are 24% less likely to incur health violations of the Safe Drinking Water Act (SDWA) than government-owned systems.
More recently, a further analysis of the PNAS dataset was conducted by Dr. Justin Adams of Encina Advisors, an economics research and statistical analysis consultancy based in California. The finding that water companies have higher rates of SDWA compliance was evident both nationally and in each of the four states analyzed: California, Texas, Pennsylvania, and New Jersey. This marks the first time a state-level analysis comparing drinking water compliance records of regulated water companies and local governments has been conducted using this dataset.