Inflow and Infiltration: A Critical Problem for Otherwise Healthy Sanitary Sewer Systems

Contrary to popular belief, sanitary sewer systems are more than just masses of piping. Underground conduits may indeed be the main event, but they can only serve their function within the proper environments. The natural and human-made features around pipes are just as important as elements like valves and gaskets, and they have major impacts on sewer functionality. When water moves from these spaces into sewers via inflow or infiltration, it can pose critical problems for wastewater municipalities and the populations they serve.

What are inflow and infiltration? Here’s a quick explainer of how these phenomena arise and what their impacts are for sewer system stakeholders and users.

Understanding How Water Gets Into Sewers

Most people know that sewer systems operate by moving water from one area to another. To perform this task, they must provide a low-resistance path that facilitates the flow of large volumes of fluid. They additionally have to be capable of accepting contaminants, such as plant debris, human refuse and other forms of waste, without clogging or backing up. This operating model may also contribute to two unique problems:

Water Inflow Basics

Inflow refers to stormwater runoff that gains entry to sanitary sewers via their links to other water diversion systems. For instance, after heavy precipitation, excessive runoff may flow into the sewer from gutters, downspouts, residential driveways, streams, building foundations or other artificial and natural structures.

In many cases, problematic inflow connections are prohibited by local zoning ordinances and building codes. That doesn’t stop them from doing damage, however, as builders and property owners can easily cause problems by linking unapproved drainage outlets to municipal sewers.

Explaining Water Infiltration

Infiltration occurs when compromised sewer facilities allow the passage of groundwater via unintended entry points. For instance, aged piping might crack and let underground aquifers bubble into the system — a natural consequence of creating a low-resistance flow path.

In other cases, improper installation or insufficient upkeep contribute to similar outcomes. Conditions that contribute to infiltration may prove more prevalent in certain areas, such as older neighborhoods and facilities that are long overdue for inspections.

The Ramifications of Infiltration and Inflow

The EPA notes that almost all sewers can be expected to experience these issues to some degree. Unfortunately, such realities don’t make inflow or infiltration any less harmful. Their impacts can be devastating for communities as well as stakeholders that want to control maintenance costs and provide effective services.

Quantifying Performance Problems

Excessive water entering sewers often leads to overflow situations. Even if such conditions stop short of being severe enough to cause flooding and large-scale catastrophes, they can easily overtax treatment facilities and contribute to shorter wastewater plant lifetimes.

Another big problem with unwanted water entry is its ability to clog piping, pumps, filters, valves and other elements with foreign material. From heightened operating costs to increased financial burdens for ratepayers, these problems have real economic and performance impacts.

Examining the Environmental Consequences

Although infiltration and inflow are commonly referred to as “clear water,” they’re anything but sanitary. For one thing, these flow channels often bear their own contamination in the form of the pollutants they pick up on their way to the sewer entry points. Once these pollutants enter the sewer system, they mix with a range of other contaminants. When overflows occur, these materials can spread across vast swaths of the natural environment. For this reason, effective stormwater management is crucial.

Exploring the Public Health Fallout

Wastewater treatment is designed to keep harmful substances away from areas of human habitation. When sewer pipes succumb to water infiltration or inflow, however, it can be extremely difficult to predict where overflows and blockages might crop up. This poses a substantial public health threat that intensifies the chances of costly liability concerns that drastically weaken communities.

How Can Water and Wastewater Agencies Fight Back?

Some of the most promising technological advances in the battle against inflow and infiltration revolve around supervisory control and data acquisition, or SCADA. By monitoring sewer networks and components at critical operating points, cloud-based SCADA systems help wastewater entities pinpoint likely sources of concern and take decisive action before things spiral out of control.

Infiltration and inflow are unavoidable realities of operating and maintaining sewer pipes and the systems they connect. The real question is whether municipalities are ready to step up and improve how they work using cloud-based SCADA software to monitor the health and functionality of their systems.

SCADA software provides automated reporting for wastewater operators so they can learn about the health and functionality of their equipment before a costly and potentially hazardous problem arises. Those that make the shift now will undoubtedly provide superior services and enhance public safety for generations to come.

Contact High Tide Technologies to learn how you can upgrade your remote monitoring system.