But public officials and environmental activists agree the final solution is very expensive and years away even after taxpayers have already spent a lot of money tackling this problem.

Reps. Annie Kuster and Chris Pappas, both Democrats, were joined by Massachusetts congressmen from the Merrimack Valley to lobby federal budget writers last week to earmark at least $500 million for states and cities to design, plan and build these storm water treatment systems.

Congress has authorized spending up to $225 million on these grants to states and communities to help share these costs.

This request, if granted, would more than double that program.

“So much of our region’s economy and way of life has been built upon the Merrimack River. Although the Merrimack remains one of our region’s greatest treasures, the impacts of outdated storm and waste water systems are being felt in communities along the river in New Hampshire and Massachusetts and jeopardize the vitality of the region,” Pappas said.

“It is incumbent upon us to update our water infrastructure so the river can thrive and support the needs of the Merrimack Valley for generations to come.”

In Manchester, most of the sewer lines collect both rainwater from streets and sewage from homes and businesses.

These combined sewers exist in 800 communities across the country including in Nashua, Berlin, Lebanon, Portsmouth and Exeter according to the New Hampshire Department of Environmental Services.

When it’s not raining, the wastewater flows through these lines to the city’s wastewater treatment before it’s discharged into the river.

But when it rains, the system can be quickly overwhelmed and then the excess of rainwater and sewage gets sent straight through outfalls into the river.

These combined sewer overflows happen so this mixture doesn’t end up backing up into streets and residential basements, city officials said.

Water quality on the Merrimack is critical since it serves as a drinking water supply for nearly 600,000 people in New Hampshire and Massachusetts.

“The Merrimack River supplies drinking water to hundreds of thousands of people and we must ensure that Granite State families and all who rely on this resource are receiving safe clean water,” Kuster said.

Last year, 800 million gallons of sewage and untreated storm water was released into the river and then out to sea.

Discharges in Manchester and Lowell, Mass., accounted for more than half that volume according to federal officials.

City officials reported in 2018 there were 177 distinct “events” of this discharge that let 364,000 gallons into the river.

“The City of Manchester has spent $100 million over the last 20 years to address combined sewer overflows, largely without financial assistance from the federal government. Without federal funding for these vital projects, it will take decades to complete these large, expensive, and much-needed wastewater projects,” Manchester Mayor Joyce Craig said in a statement.

“I want to thank Congressman Pappas and Congresswoman Kuster for fighting for this funding so that cities like Manchester can accelerate wastewater infrastructure projects that will not only improve the quality of water in the Merrimack River, but improve the lives of Manchester residents.”

The price tag to make these improvements and prevent these discharges is $1.6 billion in the two states.

“When sewage flows into the river, it threatens those jobs and our families,” said Rep. Seth Moulton, D-Mass., and a 2020 candidate for President.

“This funding is a vital step forward and one of many steps that I’ll be taking on this issue in the coming weeks. For too long, leaders in Washington have ignored this problem. It’s time to fix our aging infrastructure so people across the country don’t have to worry about the safety of their drinking water.”

Manchester Chief Engineer Frederick J. McNeill said the discharges have occurred since the early 1970s.

In March 1999 the U.S. Environmental Protection Agency issued an administrative order requiring Manchester to come up with a plan to eliminate its combined sewer overflows.

Over the next decade the city spent $58 million on Phase 1, which reduced discharges to the west side of the Merrimack River by 99 percent, officials said.

The city has proposed a Phase II, costing $165 million over a 20-year period to substantially reduce discharges on the city’s east side of the river.

Right after the Clean Water Act passed in 1972 the federal government was footing 75 percent of the total cost to make these upgrades.

In recent years federal support has declined to less than 5 percent of total costs.

Rusty Russell, executive director of the Merrimack River Watershed Council, recently poured through those documents on Manchester’s discharges.

“It may surprise you to know that there is no single source of comprehensive information on the Merrimack’s CSO (combined sewer overflow) events. We are taking the initiative to change that,” Russell recently posted to his followers on Facebook.

He authored a commentary in the Union Leader urging lawmakers from both states to approve new laws that would require real time reporting of these discharges to give timely notice about them to those concerned about water quality.

There are pending bills on the topic in Massachusetts but none filed this year in New Hampshire, Russell said.

“Does Manchester’s wastewater plant disclose how much sewage it dumps from its 15 CSO outlets during any given rainstorm? No,” Russell wrote.

“Does the city afford kayakers, anglers, jet-skiers, waders, and people walking water-loving dogs real-time notice that it is inflicting a sewage overflow upon the river and where along its five-mile stretch of CSOs this is happening? No, it doesn’t.”

The watershed group would like to see officials from all Merrimack River cities post visible flags about water quality and install backup generators at all treatment plants to prevent any such discharges due to a power loss.

Manchester Chief Engineer McNeill said the city has updated its website for more reporting on these discharges and is negotiating with the EPA on a formal reporting regimen.

klandrigan@unionleader.com