This article is provided by Cindy Barks at The Daily Courier . It explains why city leaders have decided to eliminate PVC Pipe from the city’s new water mains. Prescott, AZ has suffered decades of pipe failures from PVC pipes. Failures and breaks that have cost the city and the taxpayers millions of dollars. Prescott has decided to not allow PVC pipes to be used as water mains in the future. 

By Cindy Barks
Originally Published: February 24, 2021 7:36 p.m.
Link: Prescott eliminates use of PVC pipe for water mains

After years of discussion and multiple costly water breaks, the City of Prescott has opted to eliminate PVC pipe as a material for new water mains.

While the change is expected to make Prescott’s water mains less vulnerable to future water breaks, it also will add to the cost of building a subdivision.

In a 7-0 vote Tuesday, Feb. 23, the Prescott City Council approved a code change that effectively bans the use of polyvinyl chloride (PVC) pipes in new city water mains.

That amends the existing code, which allowed PVC pipe as an alternate material when approved by the city engineer and installed in accordance with city standards.

To help offset the expected cost increase from the use of ductile iron pipe instead of PVC, the council also agreed to several construction changes intended to bring down the overall cost of development.

LONG-TERM PROBLEM

Public Works Director Craig Dotseth told the council this week that PVC pipe began being used for water mains in Prescott in about 1985. Within 10 years of that, the pipes were experiencing notable failures, he said.

To date, the city has spent more than $4 million replacing upwards of 14,700 linear feet of the broken PVC pipe.

In 2016, the City Council discussed the matter extensively, and decided to allow developers to continue to use PVC pipe “with approval of an alteration/modification.”

In a report to the council in December 2020, Dotseth said that since 2016, private developments had used PVC pipe in 30 projects, while 44 projects used the more expensive ductile iron — 22 of which were installed after denial by the city of a PVC request.

Meanwhile, the city exclusively uses ductile iron pipe for its own water main projects, as well as in the repair replacements.

The issue went back to the council in 2020 because of a number of “catastrophic” breaks that had happened on underground PVC water mains in recent years.

City officials have maintained that PVC pipe is more vulnerable to damage from Prescott’s rocky terrain. The older PVC water mains were often installed directly on rock, which caused many of the breaks.

To prevent continuing problems with the water mains, the Public Works Department recommended eliminating PVC pipe in water mains altogether.

The council discussed the issue in December 2020 and again in January 2021, at which time the council postponed a decision for a month to allow for more discussion with the construction industry.

Public Works staff and industry representatives reportedly met digitally over the past month and came up with a number of ideas for moving forward.

On Tuesday, Dotseth told the council, “Today, we are coming forward as a united front.”

WHAT IT AFFECTS

While the amended code states, “The use of PVC pipe shall not be allowed,” the change will not affect projects that are already under construction or are already approved for an alternate/modification material, Utilities Manager Eric Bay told the council.

Dotseth said Wednesday that projects currently underway or approved for an alternate use include Westwood in the Deep Well Ranch subdivision and a phase in the Granite Dells Estates project.

Bay noted that the change also would not affect sewer mains, storm drains, or conduit installations. His presentation explained that PVC is the most common material used for sewer mains by private developers and the city.

“PVC sewer main is not pressurized, does not fail catastrophically, and can often be repaired without trenching,” stated the presentation.

‘A UNITED FRONT’

Through the recent discussions with development industry representatives, Dotseth said four recommendations had come up to help bring down the cost of development in general.

While talking with the industry representatives about the expected cost increase of $291 per lot for the use of ductile iron pipe, Dotseth said, “They asked us if there were some other things that we can work on that can have the possibility of balancing or offsetting the price increase.”

For instance, the use of recycled asphalt or concrete within the aggregate base course of roads was recommended for immediate implementation. “Absolutely, we as Public Works can stand behind that as we’ve seen it benefit our projects significantly,” Dotseth said.

Other suggestions involved adjusting materials used for storm drain installation; adjusting the “time of concentration” in storm water detention in downstream considerations; and use of recycled asphalt pavement within asphalt mixes.

Council members expressed support for the changes and the process.

“I appreciate your diligence and patience on this,” Mayor Greg Mengarelli told Dotseth and Bay. “These ideas that are coming out are very beneficial to our city. I appreciate you guys being flexible and open. We’re seeing the benefit of that right here.”

In discussing the durability of iron pipe, Councilman Phil Goode brought up the cast-iron water mains that broke over the weekend in two locations in Prescott after being in the ground for 50 to 60 years. “Ductile iron should have an even longer lifespan,” he said.

Sandy Griffis, Yavapai County Contractors Association executive director, agreed that the two sides had come together.

“It’s pretty neat when we can assemble the industry with city staff,” Griffis told the council. “And here’s proof that we developed and designed a win-win for the community, the citizens, the City of Prescott team, the industry. It’s really phenomenal.”