Houston Water Turns to SIPP Epoxy to Restore Critical Water Main

A recent project completed for Houston Water highlights the use of spray-in-place polymer (SIPP) pipe epoxy rehabilitation for water main repairs.

Background

In 2022, Houston Water began a critical rehabilitation of its potable water infrastructure. This includes a 24-in. cast iron water main at risk of failure. The pipe was significantly corroded, with heavy tuberculation and misaligned – or “kicked” – joints. This prompted the city to launch a pipe repair project.

After initial efforts fell short due to the pipe’s deteriorated condition, the city turned to local experience contractor Spray in Place Solutions (SIPS). They used advanced trenchless technology to take on the challenge.

Turning a Challenge into a Demonstration of Innovation

Initially, a local contractor was tasked with installing seal patches inside the water main. However, upon inspection, Houston Water found that internal corrosion and joint misalignment made traditional patching unviable. Seeking a more effective, long-term solution, Houston Water engaged SIPS. They wanted to evaluate the possibility of spray-in-place polymer (SIPP) pipe epoxy rehabilitation.

The owner was interested in contracting SIPS due to their history of dealing with similar situations and expertise in pipe rehabilitation. SIPS recommended a SIPP epoxy rehabilitation method and used this section of pipe as a demo opportunity. Fortunately, the owner was already interested in exploring advanced rehabilitation technology and agreed. The agreement resulted in rehabilitating a section of the pipeline. This was a section that the previous contractor passed on and the demonstration was a huge success.

In the process of awarding the project, Houston Water was convinced that the SIPP application of a high build epoxy reduced the amount of time pipes would be out of service. There was also the bonus of extending its estimated service life by over 50 years. In addition, SIPS’ crew had been providing SIPP services for more than 14 years, completing 100-plus projects and lining over 500,000 linear feet. Houston Water understood that SIPS didn’t just bring a temporary fix. Rather, they offered a long-term, structurally enhancing solution that would restore and protect the pipe for years to come.

Scope of Work and Application Process

SIPS rehabilitated the 24-in. cast iron water main using Warren Environmental’s 100 percent solids, 301-01 epoxy — a product certified for potable water use by NSF/ANSI/CAN 61 standards. This high-build epoxy is applied in a single coat and designed to provide semi-structural reinforcement. It goes beyond traditional thin-coat linings.

With SIPP already established as the method of choice, the team initiated the step-by-step application process. This ensured a durable, long-lasting pipe rehabilitation.

The SIPP application process involves several key steps:

Pipe Inspection and Cleaning

The crew began by performing CCTV inspections to assess pipe conditions. Rigorous cleaning followed using drag scrapers and high-pressure water jetting. Another inspection confirmed extensive degradation.

Surface Preparation

Proper surface preparation ensures a strong bond between the epoxy and pipe wall. This may include additional cleaning or scarifying the existing coating when multiple coats are applied. In this project, robotic equipment was used to grout the kicked joints and prepare the substrate.

Epoxy SIPP Application

Once the pipe’s surface was prepped, approximately 3 millimeters (120 mils) of Warren’s 301-01 high build epoxy was then applied using specialized equipment. The spray head is precisely controlled to achieve a uniform coating thickness and monitored throughout the process.
Final Inspection: The lining undergoes visual or camera inspection to confirm integrity. It is then disinfected and tested for bacteria according to contractor or owner requirements.

Using SIPP technology, this application sealed cracks, restored alignment, and eliminated the risk of future corrosion buildup. Unlike previous-generation coatings that merely acted as a barrier, this epoxy provided structural enhancement. It met AWWA Class III standards and exceeded ASTM 1743 Class IV strength module classification values.

With zero VOCs and an aquatic-safe formula (per ASTM E729), Warren’s epoxy ensured an environmentally friendly solution. It caused no adverse impact on water quality – key for a project involving a potable water main.

The project, which would have taken four to six weeks using open-cut replacement, was completed in just four days. Once the application was complete and the epoxy cured, the city performed tests to bring the pipe back online into their system.

Minimal Disruption, Maximum Impact

Located in a busy downtown Houston area, the project had to balance urgency with community disruption. One of SIPP’s most significant advantages was its compact footprint. SIPS operated out of two 6-ft by 6-ft pits spaced up to 650 ft apart. This allowed crews to work safely from the road shoulder instead of shutting down traffic lanes.

This reduced the need for traffic control, avoided business interruptions, and eliminated the extensive excavation and replacement typically required. Compared to excavation and replacement methods, the SIPP approach used just 5 percent of the space and 15 percent of the time. This was an added benefit to both the city and its residents.

Moreover, SIPP allowed for continuous lining without compromising service connections. Unlike cured-in-place pipe (CIPP) methods that often require robotic cutting to reopen lateral connections, SIPP preserves these connections during the spray process — down to ¾ of an inch—making it an ideal choice for water utilities. This is especially true for those prioritizing service continuity.

Overcoming the Heat

One of the project’s biggest challenges was the Texas heat. Completed in July, the pipeline reached internal temperatures of 97 F – despite being buried 6 ft underground. Thanks to SIPS’s extensive experience applying Warren’s epoxy in similar environments, and to Warren epoxy’s formulation, which is engineered to cure reliably in high humidity and elevated temperatures. The team successfully kept the project on schedule using spin-cast technology and temperature-adaptable techniques.

A Model for the Future

With the success of this project, the SIPP method proved to be not just a viable solution – but a superior one. It delivered structural enhancement, minimal disruption, environmental safety, and long-term value.

By completing the project in just four days, with reduced labor, smaller construction zones, and better environmental outcomes, SIPS and Warren Environmental demonstrated how aging infrastructure can be revitalized quickly and sustainably. This was achieved using emerging techniques.

Brandon Brandstetter is president at Warren Environmental.