Tap water in Friendswood and Webster is running yellow or green after Tropical Storm Edouard's heavy rains. Both cities say the water is safe to drink.

Friendswood officials said the city was advised by Houston city officials about elevated levels of naturally occurring minerals in the water supply, ABC13 reported Wednesday, Sept. 16. The city said samples from its water system continue to meet or exceed regulatory standards.

Edouard made landfall near Johnson Bayou, Louisiana, on Tuesday, Sept. 1, with maximum sustained winds of 60 mph. Southeast Texas received 4 to 12 inches of rain in the 24 hours that followed, according to KPRC 2 reporting on Sept. 2.

The discoloration took roughly two weeks to show up. Webster's public works department began receiving reports over the weekend of Sept. 12 from residents who noticed a greenish hue in parts of the city's water distribution system, the Houston Chronicle reported. The city launched a water quality review and posted updates on Facebook.

The Clear Lake Water Authority and Webster officials attributed the color change to naturally occurring minerals stirred up by Edouard's rainfall in the Trinity River Basin. That rainfall made the raw water supply appear murkier, even as the water treatment process continued to work, the Chronicle reported.

The U.S. Environmental Protection Agency (EPA) says water clarity, called turbidity, can be affected by runoff from weather events. Higher turbidity makes water appear cloudier.

As of Tuesday, Sept. 15, Webster confirmed the water remained discolored but reiterated it was safe to drink. The city said it would keep monitoring the distribution system and provide updates if conditions change.

Friendswood officials said the city's drinking water continues to meet or exceed regulatory standards.

Neither city has given a timeline for when the discoloration will clear.

Clear Lake area resident Seliena Corrington, who lives in the Bay Oaks subdivision, told the Houston Chronicle on Sept. 15 that the discoloration was hard to spot in small amounts. "If you take the water out and put it in a glass, you can't see it," she said, adding that it becomes more visible with depth.

Both cities say they will continue testing.

Friendswood residents with questions can call the Public Works Department at 281-996-3380 or email [email protected].