Air scouring is a safe, non-abrasive, and cost-effective method for cleaning water and sewer mains. Using existing valves and hydrants, H & S Maintenance can clean an average of 4km—and up to 8km—of mains in just six hours.
The process:
Isolate a section of the main and remove existing water with high-velocity, low-pressure air.
Introduce controlled slugs of water.
The air-and-water mixture creates a vortex that removes sediment and biofilm.
Air scouring works on all pipe types up to 300mm in diameter.
As part of our air scouring services, we offer pre- and post-cleaning water quality testing, including free and total chlorine, turbidity, and RPM testing. These tests allow water authorities to monitor changes and take action if required, ensuring the system remains safe and efficient.
Removes sediment and biofilm to improve water flows and quality.
Reduces customer complaints about discoloured water or low pressure.
Helps maintain chlorine levels and overall water safety.
We provide pre- and post-cleaning water quality testing, including:
These tests allow water authorities to monitor water quality and take action if required.
Cost-effective: Cleans mains efficiently while reducing operational costs.
Improved water quality and flow: Minimises discoloured water and reduces chemical use.
Versatile: Suitable for potable water, bore and river water, and sewer mains.
Enhanced system performance: In sewer mains, flow can increase dramatically, especially in rising mains.
H & S Maintenance uses modern, state-of-the-art equipment to deliver reliable, high-quality results across every project.
Resuspension Potential Method (RPM) testing is used to determine how dirty water mains are. Many water authorities include pre- and post-RPM testing as part of air scouring projects.
Pre-testing shows the level of sediment and biofilm in the mains.
Post-testing demonstrates the effectiveness of cleaning and informs future maintenance schedules.
RPM testing measures the capacity of sediment in a water network to resuspend when there is a controlled, moderate increase in water velocity. This provides a clear indication of how much sediment is present and how likely it is to affect water quality.
The RPM machine is connected to a hydrant, sets the required flow, and records turbidity in the water. The results are used to assess cleaning effectiveness and to plan the frequency of future maintenance for each zone.
H&S Maintenance uses modern RPM equipment to ensure precise measurements and support effective water main management.
Water main swabbing involves inserting a high-density foam swab into the main to remove sediment, barnacles, and other debris. Using existing entry and exit points such as hydrants—or by creating temporary access points—the swab travels through the pipe, scrubbing the walls and pushing loosened material out of the exit point.
Foam swabbing is effective on all main sizes and is particularly suited for long distances, with the ability to clean up to 20km of mains per day. H & S Maintenance has successfully completed projects on mains ranging from 100mm to 450mm in diameter, with distances from 2km up to 25km.
