About half of the town's sewer pipes, and a third of the town's water pipes, are in "good" condition with about 40 percent life left, according to studies of the systems presented to the Vienna Town Council on Monday night.

Wiley|Wilson, the town’s engineering firm, and environmental engineering firm GHD Inc., unveiled a pipe-by-pipe evaluation of the town’s current system and an overview of potential capital improvement projects to Council members, to help them better understand the systems' value and potential needs.

Vienna has 131 miles of water pipes and 84 miles of sewer pipes, consultants said.

Water:

• 131 miles of pipe
• 2,000 valves
• 850 hydrants
• Three storage tanks with booster pumps.

Sewer:

• 84 miles of pipes
• 2,000 manholes

In the pipe-by-pipe analysis, consultants found that 49 percent of the sewer system — 40.8 miles — and 35 percent of the water system — 43.5 miles — were "good." About 62 percent of the water system and 42 percent of the sewer system was rated "fair" by the consultants, indicating there was about 30 percent of their lives left. And 5 percent of the water system and 8.1 percent of the sewer system were rated "poor" or "failed."

Lifespan for water pipes vary depending on when they were built, and what material was used. Dennis Johnson, a town engineer, said cast iron pipe installed before 1920 (when pipes were thick) has an average life of 120 years. Forty percent life left on that type of pipe would be 48 years, he said, but could vary for pipes in different parts of town.

The majority of the water system, created largely post-WWII  in the 1960s and 70s, is built mostly of cast iron. The sewer system consists largely of concrete pipes.

"The break rates for the water system are in that middle average for utilites of similar sizes," Muckleroy said. "[But] another takeaway is understanding that as time goes on we’re going to have to invest in this stysm its not like everything is good ltes not worry about it, investments are needed."

More than $12 million in investments would need to be made over the next 10 years, consultants said.

The town is considering selling the systems. If the town keeps them, consultants said it should invest in Pipe Leak Detection and Condition Assesment technology, which would provide more data and allow Department of Public Works staff to better detect, predict and repair leaks. The town would pay $25,000 for the system in fiscal year 2013, and another $100,000 between 2017 and 2021, according to the consultants' capital improvement project projections.

Another is SCADA (Supervisory Control And Data Acquisition) technology, which would be installed at a water tank to help DPW staff better monitor tank level and water pressure, which would allow them to prevent more incidents, consultants said. The system would cost the town $75,000 each year for the next three years.

All investments proposed by consultants would increase water and sewer rates by about 6 percent each year, according to their projections. That increase does not take into account the cost of purchasing water.

Under this plan, by Fiscal Year 16-17, water and sewer rates would reach $5.16 per thousand gallons and $6.73 per thousand gallons, respectively.

If the town sold to another municipality, it would not set the rates.

For more on the studies, click here.