Smoke testing is one of the most accurate ways to find sanitary sewer leaks. It involves forcing non-toxic smoke into a line using high-powered blowers. Smoke will appear in areas where rainwater enters the clean sewer system and overburdens wastewater treatment plants. It will also reveal illegal connections, including roof, sump pumps, and yard drains.
Identifying Sources of Water Infiltration
Smoke testing is an effective method to identify where rainwater infiltrates sanitary sewer lines. This unauthorized inflow can cause wastewater treatment plant overflows and backups and increase customer sewer service costs. To conduct a smoke test, city crews force visible, non-toxic smoke into a pipe segment and survey where it exits. This technique reveals where roof or foundation drains are improperly connected to the sanitary sewer, which allows rainwater and runoff to enter the system and add extra stress to waste-treatment facilities. Different types of smoke testing equipment are available. The classic smoke candles introduced in 1961 are still the most popular tool for locating leaks. These devices use a chemical reaction to produce visible smoke. Other systems use petroleum product that is heated in the hot exhaust stream of a small engine and forced into the sanitary sewer. To prepare for a sewer smoke test, home and business owners are advised to clean out their p-traps (U-joints in sinks and bathtubs) by running water through them for a few minutes before the inspection. It’s also recommended that buildings be closed up, and all plumbing fixtures be shut off during the smoke testing period to prevent any smoke from entering the building or causing other problems such as water intrusion or sewage odor.
Identifying Leaks
Smoke testing is one of the best ways to see where unauthorized water is entering the sewer system. It involves forcing visible smoke and high volumes of air into sanitary sewer lines and surveying where the smoke exits. If the smoke exits a storm drain or the ground, it indicates that rainwater is infiltrating the clean sewer system and contributing to overflows and wastewater treatment costs. The smoke can be generated by several methods, including using the chemical reaction of zinc chloride in a device called a “smoke candle” or by burning petroleum oil inside a small engine that sits on top of a maintenance hole. During smoke testing, it is essential to pour water down all of your drains, especially ones that are rarely used, to keep them from becoming dry and potentially allowing sewer gases into the home. You should also ensure that your P-traps are filled with running water for a few minutes before the testing period.
Identifying Sources of Water Inflow
Sewer smoke testing effectively locates areas where water inflow into the sanitary sewer system occurs. It’s a relatively simple process that involves forcing visible smoke, mixed with air under moderate pressure, into the sewer pipes and surveying where it escapes. The smoke quickly shows up at connections where surface water inflow is causing problems. Field crews use a variety of methods to generate the smoke. The most common is a device called a “smoke candle.” These devices have been in use for decades. A more recent development is a gas-powered engine that injects smoke fluid into the exhaust stream. This device is more efficient than a traditional smoke candle and provides a higher volume of smoke for excellent coverage. Smoke can also appear at new floor drains, sinks, showers, un-trapped washing machines or garbage disposals, or other unauthorized connections to the sanitary sewer. It’s important to note that these illegal connections may be a health hazard as they can flow toxic sewer gases into homes and businesses. Confirmed inflow sources that smoked during the test should be photographed, documented, and, if necessary, subject to follow-up dye testing or building inspections.