In the next few weeks, both sides of U.S. Highway 377 between Davis Road and Fall Creek Highway in Granbury will undergo smoke testing.
“Smoke testing” is a method used by the city about every 10 years to determine where rainwater is getting into the sewer system and to identify leaks or other bad connections.
Back in September, the city awarded a $60,636.80 bid to Pipeline Analysis, a water treatment plant from Garland, to blow “smoke” into the pipe network, as the Lift Station 23 sewerage basin had been subject to inflow and infiltration during rain events for the last eight years.
According to the Granbury City Council agenda report from Sept. 19, inflow and infiltration have been the primary cause of many of the sanitary sewer overflows the city has experienced on Kings Plaza and 2nd Street.
The agenda report states the smoke testing procedure will consist of introducing a non-toxic smoke into sections of the sewerage basin and pressurizing it with fans, forcing the smoke out of legitimate holes such as vents and manholes and defects such as broken pipes, uncapped clean-outs and illegal connections.
As crews look for smoke coming out through holes, manhole covers, plumbing vent pipes and other locations where rainwater can get into the sewer system, they will be able to identify the areas still needing repair or rehabilitation.
Jeff Newpher, city communications manager, explained that a better term to describe the “smoke” is “vapor,” as it’s nontoxic and not harmful to people or pets. Additionally, the vapor is nonstaining, has a slight odor, is white to grey in color and does not create a fire hazard.
“These companies are experts in smoke testing,” Newpher said. “(They use) vapor that's forced into the sewer lines to see where the vapor comes out and if it comes out in unexpected places, then that indicates where there may be issues that were not visible to the naked eye. It's a really efficient way to find out where problems are and where water is getting out, and it's a way to identify the places where you'd have those types of problems or leakage in your sewer systems.”
Smoke from the test could enter homes through floor drains and unused toilets, sinks or showers. While all drains have water traps to prevent fumes from entering homes, floor drains in basements or in garages can dry up.
The city recommends residents ensure the drains in their houses have water in them to prevent smoke from entering. Residents are also encouraged to pour a bucket of water down floor drains, sinks drains, shower drains, or any toilets that haven’t been used in a month.
“We're just telling people if you've got a three-bedroom, two-bath house, and you don't use the toilet in the one bathroom and you never use the sink, just run the faucet for 30 seconds and flush the toilet just once this month, and you'll be fine,” Newpher said.
Many apartment buildings have a basement common area for laundry or storage. For apartment residents, the city recommends individuals pour water down laundry tubs or floor drains in these common areas.
The city also advises individuals to call 911 if they are not certain any smoke they see is the result of the city’s testing.
As part of this project and contract, the contractor conducting the smoke testing will notify the public beforehand with doorhangers, perform the testing for the entire basin, and submit a report of the findings.
Newpher added that as new phases and neighborhoods get added to the smoke testing, the city will notify residents of any future testing in their area.
For more information and to stay informed of other city news, visit granbury.org online.