SWAMPSCOTT – Residents will see a new charge on their water and sewer bills.At its meeting Tuesday evening, the Board of Selectmen voted to impose a quarterly base fee of $19.75 for each home. Town Administrator Andrew Maylor said the base fee distributes the cost of operating the system more equitably. He pointed out there are some residents who do not use the service for a portion of the year, which means those using the service during any given quarter bear the costs of operating the system.The Board of Selectmen voted to allow an annual senior abatement of $79 per year for seniors, who are 75 years of age or older and who use 300 (100 cubic foot) units or less annually. Maylor said the abatement would serve to offset the quarterly base fee for eligible seniors.”It provides some relief,’ he said.In addition to imposing the quarterly base fee, the Board of Selectmen voted unanimously to set the water rate at $5.22 per 100 cubic feet and the sewer rate at $4.35 per 100 cubic feet, which Maylor said is an increase of approximately 7.9 percent.According to Maylor, the combined water and sewer bill would increase by approximately $21 per quarter for the average homeowner without the quarterly base fee the water and sewer rates would increase even more than being proposed.Maylor said the town is not the only community that charges a quarterly base fee. He pointed out that in 2002, the water and sewer rates in Swampscott were among the highest in MWRA communities and now it is right in the middle in regards to the rates charged.Maylor said water and sewer rates in town dropped for two consecutive years because Town Meeting voted to use $1 million in accumulated reserves in the water and sewer enterprise fund to reduce the rates. He said the reserves have been depleted and only three to four months of operating costs are currently being held in reserve. He said to lower the amount of reserves in the water and sewer fund is not recommended and it could have an adverse effect on the town’s bond rating.