How Do I Know If I have Storm Water Infiltration in My Sewer Network?

The infiltration of storm water in a commercial or domestic sewer network can pose major detriments to humans’ health and structure integrity. On a large scale, storm water’s infiltration in a city’s sewer system is usually achieved through low gully traps, broken pipes, illegal connections, and unsealed utility holes. When this happens, it’s referred to as Inflow and Infiltration (I&I). Early detection is critical to prevent bearing the associated risks of storm water infiltration. This article will discuss pointers that’ll help you know if you have an I & I problem in your sewer network.

Identifying the problem

The following clues give away a storm water infiltration problem;

  • Your pump runs for hours, and the storm water that enters the wastewater network through gully traps, roofs, or illegal connections, AKA inflow, increases significantly during storm events.
  • The hydraulic loading of wastewater treatment plants increases significantly after rainfall.
  • A significant increase in inflow during dry weather conditions as compared to past months.
  • Overflows in the collection systems.

Now, with all these clues, you can identify your storm water problem, but you’ll still have to locate the source of the problem. Hence for source detection, you can practice any of these methods:

  • Private inspections: This is where your property would be inspected. Here, visual assessments of the sewer network will be conducted.
  • CCTV: This is where professionals utilize a camera to relay visual information on the sewer network condition. Here, pipes in need of rehabilitation, replacement, or pipe relining are identified.
  • Manhole inspection: This is where you can identify the leaks from broken benches and joints from tree root intrusion or design failure.
  • Smoke testing: Smoke testing locates I&I sources by identifying cross-connections of storm water drains, broken pipes, and unsealed utility holes into your sewer network.

For smoke testing, the process commences with a fog machine that generates smoke into the sewer system via a motorized blower unit. Once this is done, the natural venting of the system begins. This is where the generated smoke is drawn into various openings, including a storm water sump or pipe. Hence, if a shallow pipe in your sewer system is broken, this smoke will penetrate up through the ground and will be immediately seen. In essence, where there’s smoke, there’s evidence of an illegal sewer system connection. Now, because smoke from different components can be toxic if inhaled, PPS employs a non-residual thermal fog with zero traces of carbon monoxide—thus making the process free of toxicity and completely safe. Once smoke testing is complete, a licensed and accredited plumbing company like PPS can provide comprehensive reports on the findings. This, of course, will be inclusive of photos as evidence of illegal connections.


Storm water infiltration can be very detrimental to human health and the integrity of the property or structure. This is why early detection of the problem and identification of its source is mandatory. Luckily, by employing smoke testing, which poses no health risks, adequate corrective measures can be taken in time.