What is inflow & infiltration?

Inflow and infiltration (I&I) are terms for the ways that stormwater runoff and groundwater (clear water) make their way into sanitary sewer pipes. With inflow, stormwater rapidly flows into sewers via roof drain downspouts, yard drains, storm-sewer cross connections and faulty manhole covers. Inflow is greatest during major storm events and can more than triple wastewater volumes. Infiltration occurs when groundwater water seeps into sanitary sewer pipes through cracks, leaky pipe joints and/or deteriorated manholes.

Why I&I Matters

Excessive I&I in the sewer system creates multiple problems:

• Expensive Treatment: Once stormwater and groundwater mix with wastewater, all the water is treated. This is expensive and impacts the regional system. Reducing excessive I&I in the system saves millions of dollars.
• Reduced System Capacity: Additional water that enters the wastewater system through I&I flows within fixed-capacity sewer pipes. The additional flow consumes capacity that was built to accommodate wastewater flows from existing properties and new developments. During major rain events, the additional flow can exceed the available sewer system capacity, causing overflow issues.
• Water Quality: Exceeding the capacity of the sewer system can result in wastewater overflows and spills into nearby waterways, affecting the water quality.

How the City is Reducing I&I

To support its five-year initiative to reduce inflow and infiltration (I&I), the City of Fort Lauderdale is implementing a comprehensive program that includes Sewer System Rehabilitation, Sewer Pipe Video Inspections, Overnight Sewer System Inspections and Sewer Smoke Testing. These activities are being conducted across the City’s approximately 186 sewer basins. By evaluating each basin individually, the City can identify where stormwater or groundwater is entering the sanitary sewer system and prioritize improvements where they are most needed. Details on these efforts are provided below.

Inflow & Infiltration Reduction Program: Sewer System Rehabilitation

The City of Fort Lauderdale is working with LMK Pipe Renewal to make improvements to the City’s sewer system in areas where inspections and smoke testing have identified minor defects. The project will start with crews sending cameras into the sewer system to check its condition before and after repairs. They’ll also install new access points called cleanouts, replace or fix short sections of sewer pipes that connect properties to the main sewer line and make repairs inside manholes.

Review the following materials to learn more about upcoming sewer system rehabilitation work:

Inflow & Infiltration Reduction Program: Sewer Pipe Video Inspections

The City of Fort Lauderdale is working with Insituform Technologies to inspect sewer mains and laterals throughout the City’s sewer system. Crews will access sewer lines through manholes and record videos within the pipes to document their condition. The results of this analysis will be used to plan future sewer system improvement projects. Inspections are expected to be completed in May 2026.

Review the following materials to learn more about upcoming sewer pipe video inspections:

Inflow & Infiltration Reduction Program: Overnight Sewer System Inspections

The City of Fort Lauderdale is working with Ardurra Group Inc. to study the flow of wastewater throughout the City’s sewer system over the next three years. This flow analysis is part of the City’s ongoing efforts to identify portions of the sewer system where stormwater and groundwater are possibly entering the system, which leads to problems such as increased treatment cost and reduced system capacity. The results of this analysis will be used to plan future sewer system improvement projects.

Review the following materials to learn more about upcoming overnight sewer system inspections:

Inflow & Infiltration Reduction Program: Sewer Smoke Testing

The City of Fort Lauderdale is working with Ardurra Group Inc. to conduct smoke testing throughout Fort Lauderdale over the next three years. This common procedure involves blowing smoke through sewer pipes to locate defects that would allow stormwater and groundwater to enter the sewer system. The smoke being used is odorless, non-toxic, non-staining, does not create a fire hazard and will clear within 30 minutes with proper ventilation. Smoke should not enter private properties if they are properly plumbed and vented and if water traps contain water. If smoke enters private property, please ventilate the area, and notify nearby field technicians. 

Review the following materials to learn more about upcoming sewer smoke testing:

How can the community help with I&I reduction efforts?

A significant level of I&I occurs on private property. The City will be engaging in efforts to involve and educate neighbors on how they can help reduce I&I within the sanitary sewer system.

1. Avoid planting trees and shrubs over sewer lines on private property (known as sewer laterals). The roots can damage the structure of the sewer pipes and cause leaks.
2. Make sure that sewer cleanouts are properly capped. The plastic caps tend to be broken by lawn mowers. Replacement lids are available at local hardware stores.
3. Proactively replace any known broken, leaky or problem sections of sewer pipe that are located on your property.

For more information or questions, contact:

Inflow and Infiltration Program Hotline
877-332-4037 or ftlii@ardurra.com 

City of Fort Lauderdale Customer Service Center
954-828-8000 or lauderserv@fortlauderdale.gov

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