Despite ongoing efforts from the city of Plano to monitor its sewer system, heavy rains in 2018 have resulted in approximately 2.1 million gallons of sewage overflowing out of manholes, according to city reports.

The city of Plano has reported seven sewer overflows in 2018—three of which took place at the 5500 block of W. Plano Parkway. Plano Public Works director Gerald Cosgrove said he believes the city will need to improve the system. The most recent overflow occurred Monday in the amount of 100,000 gallons at 5401 W. Park Blvd., Plano.

“Those [overflows on Sept. 22]  were because of wet weather, and those are ones where there’s so much rainwater getting into the system that it exceeded the capacity of the line,” Cosgrove said. “Now I can tell you that in the case of two of those are totally our responsibility, and we have a wastewater project underway that’s going to evaluate the system and determine where we need to make improvements. I anticipate this is a scenario that we are going to have to make improvements in.”

Cosgrove said there are two ways overflows can occur: when the system is inundated with water beyond its capacity, including during heavy rainfall; and when objects either slow or block the flow of the system.

Some of the overflows have flowed into nearby creeks, such as the White Rock Creek and Rowlett Creek. The North Texas Municipal Water District has cautioned residents in the past to avoid contact with waste material, soil, or water in the area that may have been affected by the overflow.

A spokesperson for the Texas Commission on Environmental Quality said the number of overflows the city of Plano has reported is not abnormal compared to other cities in the region.

In fact, the city of Frisco reported in February approximately 2 million gallons of sewage had overflowed from manholes linked to heavy rain at the time.

The NTMWD also reported Sept. 22 that 273,000 gallons of partially treated wastewater had "discharged from various plant locations" at their Rowlett Creek Wastewater Treatment Plant in Plano. Additionally, 27,000 gallons of wastewater overflowed at the head of the plant. Those discharges flowed into Rowlett Creek, according to a news release.

In terms of prevention, Cosgrove said there is little short-term action the city can take to mitigate future overflows.

“There’s not a lot of prevention,” Cosgrove said. “More of it is … monitoring. We have devices out in the system in the strategic points that tell us when the flows are getting high. We don’t have every location covered, but we have a lot of them.”

Part of that monitoring includes determining where excess water may be entering into the system without city authorization, repairing system leaks, expanding capacity and cleaning up affected sites.

“If there is any visible solids we always want to get rid of all those, and just clean up the area the best we can without doing any more damage than we have already done,” Cosgrove said.

See the dates, locations and volume of all seven sewage overflows reported by the city of Plano below:

  • Feb. 21
    1.1 million gallons
    5510 W. Plano Parkway

  • March 1
    363,150 gallons
    5510 W. Plano Parkway

  • Sept. 22
    100,000 gallons
    3100 block of San Simeon Way

  • Sept. 22
    100,000 gallons
    5500 block of W. Plano Parkway

  • Oct. 9
    159,900 gallons
    5401 W. Park Blvd., Plano

  • Oct. 13
    174,180 gallons
    5401 W. Park Blvd., Plano

  • Oct. 15
    100,000 gallons
    5401 W. Park Blvd., Plano


Editor's note: This story has been updated to include information about the most recent sewage overflows that took place Oct. 13 and Oct. 15.