Frequently Asked Questions

What exactly is a Smoke Test?
A three-man crew from St. Johns County Utility Department (SJCUD) will use a high capacity blower technique to test each sewer line with smoke. Smoke blowers are placed on manholes and smoke is blown through the sewer system. Any location where smoke is identified during the test, except plumbing vent stacks, is a potential I/I source for storm water to enter the sewer system. These locations will be documented via pictures and sketches.

What is the benefit to the County for performing a Smoke Test?
Smoke testing is one technique utilized to identify sections of sewers that may exhibit inflow during heavy rainfall. Smoke testing is best used to detect inflow sources such as roof downspouts, driveway, yard and area drains, foundation drains, faulty connections, and storm water drainage system cross connections. It can also detect structural damages and leaking joints in sewer pipes.

How will residents know when Smoke Testing will be performed in their neighborhoods?
Prior to beginning the smoke testing, SJCUD will give notices to all homes/buildings on the streets to be smoke tested at least 24 to 48 hours in advance. For smoke testing schedules view the Utility Notices Calendar. For planned smoke testing areas, view our interactive maps.

How are County crews recognizable in the field?
SJCUD personnel are uniformed and carry identification badges. Crew members operate from vehicles with proper signage for ease of recognition.

Is the smoke that is used hazardous?
The smoke that comes out of the vent stacks on houses or holes in the ground is non-toxic, harmless. It does not create a fire hazard. St. Johns County Sheriff and Fire Departments will be made aware of the test areas and schedule.

Do residents have to do anything to prepare their homes for Smoke Testing?
Plumbing drain traps need to be filled with water to prevent the smoke from entering the building. Run the faucet for 30-60 seconds or pour about 3 cups of water in floor and sink drains, filling the traps. Make sure to check seldom used floor drains and plumbing fixtures in your home. If smoke does enter, the resident should consult a licensed plumber. If smoke from the testing can enter through faulty plumbing, the potential exists for dangerous sewer gases to also enter the home.

Does the resident need to be home when the Smoke Testing is performed?
Homeowners do not need to be home and at no time will field crews need to enter the residence. Field inspectors will be documenting the testing, taking photos and measuring distances so that the defects may be found at a later date and repaired.

What happens after the smoke testing has been completed?
SJCUD will notify residents who need to make corrections with a letter explaining the nature of defect found, ways to correct it, and a list of licensed sewer contractors who can make corrections, if need be. Again, most corrections can be easy fixes, such as disconnecting a downspout from the ground and letting the water flow above ground away from the home.






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