Goodyear accepts TTHM consent order as carbon treatment deadline looms

Goodyear accepts TTHM consent order as carbon treatment deadline loomsGoodyear City Council has unanimously authorised a consent order with Maricopa County Environmental Services Department after TTHM running annual averages exceeded the 0.080mg/L limit at two distribution-system sampling points in the second and third quarters of 2026. The city aims to have two trailer-mounted granular activated carbon vessels operating by the end of October.

Council approved the consent order 6-0, authorising the Water Services Director to execute the agreement with Maricopa County Environmental Services Department.

TTHM running annual averages reached 0.081mg/L and 0.084mg/L in the second quarter, followed by 0.082mg/L and 0.086mg/L in the third quarter, against a 0.080mg/L limit.

Goodyear will install trailer-mounted GAC vessels at Reservoirs 13 and 23, with equipment expected for delivery on October 2 after weather delayed an earlier delivery.

The consent order requires installation, activation and construction approvals within 120 days of its effective date, followed by monthly pre- and post-treatment sampling in addition to quarterly compliance testing.

The city previously approved $2 million for the two GAC vessels using savings from brine-management projects; annual maintenance is estimated at $100,000.

Goodyear City Council has approved a consent order with Maricopa County Environmental Services Department (MCESD), formalising the city’s corrective programme after repeated exceedances of the drinking-water limit for total trihalomethanes (TTHMs). The council voted 6-0 on 28 September to authorise Water Services Director Barbara Chappell to enter the agreement. The order follows running annual average exceedances at two of the city’s eight TTHM compliance monitoring locations during both the second and third quarters of 2026. The federal maximum contaminant level for TTHMs is 0.080mg/L. Goodyear recorded second-quarter running annual averages of 0.081mg/L and 0.084mg/L at the two locations. Third-quarter averages were 0.082mg/L and 0.086mg/L. TTHMs are disinfection byproducts formed when chlorine reacts with naturally occurring organic material. Chappell told the council that groundwater historically formed the basis of Goodyear’s supply and has low organic content, while surface water contains greater levels of organics associated with algae and plant material. The city began using surface water in 2022 and had already installed aeration at two potable-water reservoirs, but recent higher bromoform levels have reduced the effectiveness of the existing mitigation measures. Under the consent order, Goodyear must obtain expedited approvals to construct, install and activate trailer-mounted granular activated carbon vessels at Reservoirs 13 and 23 within 120 days of the agreement taking effect. It must also obtain MCESD approval of the completed construction. The temporary GAC units are intended to remove organics before they react with chlorine and form additional TTHMs in the distribution system. Chappell said the affected water meets standards when leaving the surface-water treatment plant and booster station, with the issue occurring nearer customers in the distribution system. The GAC units had been ordered and were expected to arrive on 2 October after rain delayed delivery. Although the county compliance clock had not started, Chappell said the city intended to have the units operating by the end of October. Council had previously approved $2 million for purchase and installation, using savings from Water Services’ brine-management projects. Estimated annual maintenance costs are $100,000. Once construction approval is issued, the city must take monthly TTHM samples at each site, both before and after GAC treatment, during the first seven days of each month and submit results within 48 hours of receiving them. Post-treatment samples must remain below 0.080mg/L. The monthly programme is additional to required quarterly compliance sampling. The order remains in force until Goodyear submits four quarterly compliance samples showing locational running annual averages below the TTHM limit at the two affected points. Failure to comply could expose the city to civil penalties of up to $1,000 per day, capped at $10,000 for each violation. Chappell told councillors the water remained safe to drink and that residents did not need to take action. The city issued a public notice after the second-quarter exceedance and was sending a second notification following the third-quarter results.