LYNN – Ratepayers could pay an additional $15 to $22, or about 2.5 percent more, for water and sewer service this summer depending on how much water they use.Homeowners who use 10,000 cubic feet of water annually would see their combined rate increase from $8.66 currently to $8.88. Rate-payers who pay about $606 annually to use 7,000 cubic feet of water would see a $15.40 increase.”It’s a modest increase,” Water and Sewer Commission Treasurer David Travers told commissioners this week. The commission is holding a public hearing on the increase on June 4, at 6 p.m. in its 400 Parkland Ave. meeting room. The five commissioners will vote on the proposed hike on June 9.The commissioners split last June over increasing the combined rate from $7.76 to $8.66 with Commission Chairman William Trahant Jr. and Wayne Lozzi voting against the hike.Commissioners Frank Zipper, Scott McPherson and Walter Proodian voted for the increase.By contrast, rate information provided last year by the Massachusetts Water Resource Authority indicated that residents in MWRA member communities like Nahant pay over $1,400 a year in water and sewer rates.Peabody residents paid about $578 in combined rates last year.A return to a 2.5 percent rate increase locally would signal an end to several years of significant rate hikes, including a 14 percent increase in 2006 and last year’s 11 percent jump.”Hopefully we’ve climbed the hurdle and got rates to back to where they should be,” Travers said Tuesday.Travers and other Water and Sewer officials have blamed rate increases on declining water use and rising costs including health insurance and fuel expenses.The commission’s budget recommendation for the next year will dictate the commission’s rate vote. The proposed budget is $663,000 higher than the current $25.1 million spending plan.Added costs include hikes in fringe benefits and a $10,000 increase in legal fees paid to collective bargaining counsel. Travers said fringe benefits include retirement benefits, health insurance and workers compensation.The commissioners are also considering a $2.6 million increase in spending on long-term projects including completing the stalled combined storm sewer project (CSO).With a federal mandate to end discharges of partially treated sewer into the ocean just over a year away, the commission needs to obtain federal and state environmental approval to finish building separate storm drain and sewage pipe systems.The commission is years ahead of many communities in Massachusetts in terms of CSO compliance, but major construction on local separation projects stalled in 2004 when the commission fired contractor USFilter.That decision ended up in court and legal costs associated with the firing are projected to total $500,000 this year and another half million in 2009.