Residents in Montgomery and Prince George's counties will soon see changes in their water bills as their utility seeks to make them more predictable and fair to larger households.

Whether customers of the Washington Suburban Sanitary Commission will pay more or less will depend on how much water they use and which pricing system the utility's board adopts in June.

Under three proposals that the WSSC staff recommended to the board Wednesday, households with one or two people generally would see higher bills while those with nine or more would pay less. Under one option, a three-person household with "average" water consumption would pay about $4.60 more per quarter. That same household would pay $4.80 or $21.30 less per quarter under the other two options.

The Maryland Public Service Commission ordered WSSC in March to change its pricing system after ruling that it is "unduly discriminatory" and "unreasonable" because it can cause larger households to pay more per gallon.

WSSC provides water and sewer services to nearly 2 million people in the Washington suburbs.

WSSC officials say they also need a more stable revenue stream to upgrade aging pipes, pumps and other infrastructure. Those costs are mounting even while water consumption drops as more homes are renovated with low-flow toilets, shower heads and appliances.

Carla A. Reid, WSSC's general manager, told board members the utility believes "very strongly" that any of the three proposals would meet the public service commission's order that WSSC come up with a "reasonable" pricing system.

She said the proposals also reflect what WSSC heard from customers at 20 public meetings and hearings.

A new rate structure will take effect in July 2019, after WSSC can update its billing system, officials said.

All three options would keep a tiered system that seeks to encourage conservation by charging more per gallon as customers use more water. However, all three would come with a big change.

WSSC is believed to be the only U.S. water utility to charge the highest-tier rate for the entire bill, going back to the first drop — and that can lead to drastic fluctuations in bills depending on water usage. Under the new proposals, WSSC would follow the industry standard of charging customers for water usage that falls within each tier.

The proposals also would reduce the number of pricing tiers from 16 to three or four.

WSSC officials say the changes will keep customers' bills more stable.

While some customers will pay more and some less, WSSC officials say, the changes are designed to bring in the same amount of money overall that WSSC collects now.

"We still want to encourage conservation, but this is a more fair and sensible way to do it," said Joe Beach, WSSC's chief financial officer.

However, Richard Boltuck, the Montgomery resident who filed the pricing discrimination complaint that led to the public service commission's order, said keeping a tiered system would still leave larger households paying more per gallon.

Under one of the proposals, he said, seven people in one home would pay $523 more per year than if each of them lived alone.

Boltuck, a retired economist, said he believes WSSC won't do more to even out the costs because it doesn't want to face political pushback from customers who live alone or with one other person.

"They're making it better, but they still want to avoid complaints from smaller households," Boltuck said. "They're really just locking in an inequity."