Anna Wise's shiny new black water softener uses about 75% less salt than an outdated water softener with a timer clock. It has a meter to measure water flow, softening only when necessary.

That means fewer trips to the basement with a bag of salt.

"I don't want to dump stuff in the environment that I don't have to," Wise said.

Water softeners are a major source of the chloride poisoning in Minnesota's lakes, rivers and streams. The substance is toxic to fish and aquatic life, and it's a permanent pollutant that does not degrade or go away. In fact, chloride pollution is growing faster than most other water pollutants statewide, state pollution regulators say, and they're ratcheting up efforts to kick our addiction to the salt.

De-icing salt dumped on roads, sidewalks and parking lots remains the No. 1 culprit, contributing about 42% of the chloride fouling surface waters, according to University of Minnesota research. Farm fertilizers, including manure spread on fields, are No 2.

No. 3 is wastewater treatment plants and septic systems — and most of the chloride in those systems comes from the water softeners in homes and businesses.

"If your wastewater treatment plant is discharging to a lake, river or stream, your salt is running directly into a lake, river or stream," said Sara Heger, a research engineer at the U's Water Resources Center. "The wastewater treatment plant is not removing any of the chloride. There's really no cost-effective easy way to remove it.

"We need to stop it on the front end."

Easier said than done. Water softeners are not top of mind for most homeowners. Most people are unaware the softeners have such an outsized environmental impact, and homeowners are loath to replace an expensive appliance that hasn't died.

"We treat it like the dishwasher, where we just install it and hope it keeps working," said Brooke Asleson, water pollution prevention coordinator at the Minnesota Pollution Control Agency (MPCA). "We need the public to understand their role in this."

Water softeners remove naturally occurring minerals such as calcium in water by mixing the water with sodium chloride or potassium chloride. Chloride is a byproduct.

Heger questioned whether residents in Minneapolis or St. Paul need to soften their water, given that most of it comes from the Mississippi River and other surface waters and is relatively soft. Water hardness is measured by grains per gallon of calcium carbonate; 3.5 grains or less is relatively soft.

If you do need a softener, U researchers recommend getting one that removes at least 4,000 grains of hardness per pound of salt, a measure called the salt efficiency or brine efficiency.

Jeff Hill, chief executive of the Minnesota company who made Wise's water softener, Robert B. Hill Co., said the company started making the demand-initiated softeners many years ago "just to save money on salt.

"Now it's even more important," he said.

The MPCA has been promoting chloride-reduction ordinances for cities to adopt and model rebate programs to help defray costs for homeowners. The state's first-ever Chloride Management Plan will be finalized this spring, making Minnesota the first to have one, Asleson said.

This past week Rep. Jeff Brand, DFL-St. Peter, introduced a measure to give the MPCA $1 million for grants to help create incentives for homeowners to upgrade their softeners. Priority would go to people in areas with a chloride problem.

Meanwhile, the agency is evaluating the chloride data from wastewater treatment facilities around the state. It has identified about 100 municipalities with a "reasonable potential" for a chloride problem. As their five-year federal water quality permits expire, the MPCA notifies the city if the chloride in their discharge is too high, and it sets a chloride limit that varies by facility.

One approach is eliminating the need for all the old, salt-thirsty units in homes and business by having the municipality pre-soften everyone's water at the water treatment plant before it's piped out for use. That's a costly upgrade, Asleson said, and most cities won't undertake it unless they also need to address other pollutants.

The cities of Pipestone and Morris decided to centralize it, using money from the state's Clean Water Revolving Fund, a state- and federally funded program for municipal infrastructure projects related to water quality. Marshall and Lakefield have also tapped the fund to centralize water softening. Wells, Willmar and Sacred Heart are in the process.

Lakefield, in southwest Minnesota, will break ground on its $2.8 million addition in April.

Kelly Rasche, administrative clerk for both the city and Lakefield Public Utilities, said the city has been inserting notices in utility bills alerting residents to the project. They're also informing residents that they will need to actually remove their disconnected units from the building because unused ones can grow bacteria that could contaminate water if someone accidentally hooks the unit back up.

The change isn't sitting well with everyone.

"At this point there's some pushback from residents because we're telling them what to do," Rasche said.

Residents say they're skeptical the city will get the water soft enough, Rasche said.

The city is exploring creating a rebate, a zero-interest loan program or something else to help residents haul away disconnected softeners. "We don't know what that something is yet," she said.

Jennifer Bjorhus • 612-673-4683