ROCKFORD — A year after the average sewage bill went up by 10.6%, residential customers in Rockford and much of Winnebago County are facing another increase.

The average residential customer's Four Rivers Sanitation Authority wastewater bill will go up by an estimated $3.11 a month starting in May. That is another nearly 9% hike on top of the previous increase.

The total average monthly bill is projected to increase to $38.09 or $114.08 a quarter.

That total includes an $8.57 per quarter "customer charge" — a standard fee that all residential waste water treatment customers pay. That fee has increased 31% since 2020 when it was $6.54.

And it includes a new charge for phosphorous removal that was introduced in 2021.

Four Rivers Sanitation Authority Executive Director Tim Hanson said the increases are needed to complete a 10-year modernization of its 90-acre Kishwaukee Street campus.

Increasing user fees reduces borrowing and cuts down on interest payments needed to comply with new Environmental Protection Agency requirements to reduce phosphorous and nitrogen in its effluent by 2030, Hanson said.

The requirements amount to an unfunded mandate, Hanson said.

Here is what you need to know.

Waste water treatment rates are rising as the Four Rivers Sanitation Authority modernizes its Kishwaukee Street plant.

Four Rivers treats 40 million gallons of sewage a day flushed from toilets across Rockford and much of Winnebago County. Hanson says its mission is to protect the environment from the sewage we produce.

Each year, 11,000 tons of solid waste that is strained from sewage pumped to the facility is turned into fertilizer. And 1.5 billion gallons of waste water a year is treated, cleaned and released into the Rock River.

Formerly known as the Rock River Water Reclamation District, the plant opened in 1932 and treats sewage for residents and businesses in a 100-square-mile area.

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"If that thing shuts down you are going to back up the entire city of Rockford," Hanson said. "You are going to have (sewage) in everybody's basement. We have to continually run this thing. And keep in mind this 90-year-old equipment has been running non-stop for 90 years." 

Last year, the district operated with a $53.6 million budget. Of that, $43.8 million or about 82% came from user fees while another $4.8 million or nearly 9% was budgeted from property taxes.

Despite the coming increases, Hanson said the Four Rivers charges are about "middle of the pack" compared with other waste water treatment systems.

Those bills average from $62 a quarter in Belvidere on the low end to $217 a quarter in South Beloit on the high end, according to information provided by Four Rivers. The median among sewage treatment system quarterly bills is $122, according to the data.

Four Rivers bills have six components charged based on water consumption.

Those components include the quarterly "customer charge," charges for water discharged into the sanitary sewer system, the "biochemical oxygen demand," amount of solids flushed and ammonia removal.

A sixth component was added in 2021 to pay for the removal of phosphorous, which costs $3.44 per pound. How much money was raised with the new fee in its first year was not immediately available.

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Hanson said the Four Rivers Sanitation Authority — named for the Rock, Kishwaukee, Pecatonica and Sugar rivers in the watershed — is in the midst of an 10-year, estimated $200 million plan to modernize its plant and operations.

Upgrades must be done by a Jan. 1, 2030 deadline, Hanson said.

That's the deadline for Illinois waste water districts to comply with EPA regulations to reduce environmentally harmful nutrients and phosphorous they discharge.

Nitrogen and phosphorous released into the watershed from farming, waste water treatment and lawn fertilizing enter the Mississippi River basin. It flows to the Gulf of Mexico where it creates a "dead zone" each summer. The dead zone drives away fish and kills marine life off the coasts of Texas and Louisiana

The first construction project needed to comply with the regulations by 2030 is construction of a $20 million primary filtration facility. Construction is expected to start this year. Hanson said a second needed filtration system is scheduled for construction in 2024.

Jeff Kolkey: (815) 987-1374; jkolkey@rrstar.com; @jeffkolkey