Water Treatment

PFAS Treatment

In 2022, the City of Wilmington sampled for per- and polyfluoroalkyl substances (PFAS) levels in drinking water, while in 2023, they conducted tests for 29 PFAS as part of the U.S. EPA's Unregulated Contaminant Monitoring Rule (UCMR). PFAS chemicals vary in risk, so comparing results for different chemicals isn't advisable.  For more information on PFAS, visit our PFAS page.

  • We are voluntarily testing our water quarterly to gather the best data possible to guide future decision-making and keep our customers informed. 
  • We will continue to coordinate and collaborate with state and federal regulatory agencies regarding ongoing research and rule-making developments.
  • We have chosen to take part in legal action that seeks to compensate Wilmington for our PFAS-related efforts.
  • We will continue openly communicating about PFAS, and we encourage our customers to review our Water Quality Reports.
  • We are examining strategies to effectively address PFAS compounds through our water treatment process.

Regardless of the challenges posed by PFAS, the City of Wilmington is committed to providing safe, reliable drinking water.

Membrane Filtration

In 2013, Wilmington Water unveiled Delaware’s first membrane water treatment plant. The City’s oldest water treatment facility, the Brandywine Filter Plant (BFP), was originally constructed in the early 1900s and had undergone numerous upgrades over the years. Much of the primary treatment infrastructure was over 50 years old. Due to its age and evolving regulations, the BFP required a significant upgrade, transitioning from conventional sand filtration to membrane treatment technology. The new membrane plant began producing water on June 26, 2013.

The purpose of membranes was the same as that of a conventional sand filter: to remove particulates, including pathogens and bacteria, from a water source. However, instead of using beds of packed sand to filter out these contaminants, membrane systems utilized tiny hollow fibers to purify the water. These fibers functioned like straws with numerous small holes along their sides, each hole 10 times smaller than the diameter of the finest human hair. Filtration occurred as water was forced through these microscopic holes from the outside of the "straw" to the inside. Once inside, the water could be collected, disinfected, and delivered to customers.

The new membrane plant was capable of producing an average of 7 million gallons of water daily. Water produced by the BFP was available for distribution throughout the City, along with water produced at the Porter Filter Plant. Although the filtration processes at each plant differed, customers did not notice a difference, as both facilities produced high-quality water that met or exceeded all regulatory standards.

The membrane plant still runs today and exemplifies the City’s commitment to ensuring safe and reliable drinking water for its customers.

Porter Reservoir