Somewhere between a fifth and a third of every litre a water utility puts into distribution never reaches a customer. That is what non-revenue water figures look like across most European and North American utilities, and the pressure to bring the number down is the single largest driver of capital investment in the sector right now. The trouble is that opening the road to replace ageing trunk mains is neither affordable at the scale required nor politically survivable in most urban catchments. Trenchless rehabilitation has become the practical route, and CIPP has been the reference method for potable water networks since Insituform invented the technology in 1971. Today, InsituMain Pressure is the CIPP system Insituform manufactures specifically for pressure pipe applications, including drinking water mains.
Why Drinking Water Networks Are a Rehabilitation Priority
Most of the drinking water asset base in service today was laid decades before current materials science, current jointing techniques, or current asset management economics existed. Cast iron trunk mains from the pre-war era carry internal corrosion pits and joint leakage. Asbestos cement runs installed through the post-war expansion are brittle under modern traffic loading and carry a disposal cost the day they come out of the ground. Early ductile iron and steel from later network expansions are approaching the same end-of-design-life window at the same time.
Utilities are now under regulatory pressure on several fronts at once:
- Statutory leakage reduction targets, with penalties attached in most regulated markets
- Consumer service standards on supply interruption duration and frequency
- Environmental permit obligations tied to distribution network integrity
- Reporting on non-revenue water, unaccounted-for-water, and network resilience metrics
Full replacement across an aged network would consume decades of capex allowance. Targeted rehabilitation is what closes the gap between the network utilities have and the performance regulators require.
Trenchless Water Main Rehabilitation Explained
Trenchless pipe rehabilitation installs a new pipe inside an existing host main without excavating the run. A resin-impregnated composite liner is pulled or inverted into the host, then cured in place to form a jointless, corrosion-resistant pipe-within-a-pipe. The result is fully structural, rated to carry internal working pressure independently of the aged host wall, and designed for the same external load envelope as the original main.
The difference the method makes on delivery is straightforward:
- Access excavations only at chambers, hydrants or purpose-cut pits, so most of the run stays buried and undisturbed
- Rehabilitation sections completed in days rather than weeks, so customer supply outages fit inside planned service windows
- No wholesale road reinstatement, so surface works stay minimal and community disruption stays contained
- No large-scale open trench alongside gas, electricity or telecoms, so third-party utility risk drops sharply
For readers new to CIPP for drinking water applications, our earlier post on CIPP for water and sewer pipes covers the base ground.
Inside the InsituMain Pressure System for Drinking Water Pipelines
InsituMain Pressure is the pressure pipe liner in the Insituform CIPP range. The composite is saturated with a thermosetting epoxy resin at an authorised Insituform wetout facility or on the jobsite, then inserted into the host main by pull-in or inversion under water or air pressure. Hot water or steam circulates through the tube to cure the resin. Once cure is verified, service connections on the original host pipe are robotically reinstated from inside the lined main using remote-operated cutting tools.
The specification envelope:
- Diameter range from 200mm to 1,200mm
- Internal pressure rating of 250+ psi
- Bends up to 45°
- Host pipes: cast iron, ductile iron, steel, asbestos cement, reinforced concrete and thermoplastic
- Mechanical properties exceed ASTM F1216 and ASTM F1743
Drinking water applications carry additional regulatory requirements on any resin that comes into contact with the water. NSF/ANSI Standard 61 covers this in North America, KIWA in Europe, with other national schemes elsewhere. Insituform pairs the InsituMain liner with drinking-water-approved resin systems, matched to the regulatory framework of each project. On the 600mm cast iron main under an Amsterdam canal, for example, the liner was paired with a KIWA-ATA-approved resin engineered specifically for potable water contact, and drinking water service to the city centre was restored inside five working days.
Materials, Equipment and Manufacturer Standards Behind a Successful Project
The supply chain around a drinking water rehabilitation project has more moving parts than any single spec document suggests. The liner and resin are the primary specified system. Around them sits a set of consumables and pipeline rehabilitation equipment that has to arrive on site sized, matched and ready to work with the primary system, or the programme slips on the first cure.
What a drinking water spec should account for:
- Liner engineered to the specified diameter, wall thickness and stiffness class
- Resin system certified for potable water contact, matched to the specified cure method
- Glide foil, canvas jacket and calibration hoses, sized to the liner and shot length
- Cleaning and pre-installation equipment, including CCTV and jetting rigs
- Cure equipment sized to the shot length and cure schedule
Our approach at Insituform is to manufacture the liner, resin, glide foil, canvas jacket and calibration hoses in-house, and to work with vetted equipment partners for cleaning, inspection and cure. That matters on a drinking water programme because most of the project risk on a CIPP install sits at the joins between different suppliers, and consolidating the components removes it. Every liner we produce carries 28 quality control checks from facilities certified to the ISO 9001:2015 standard by SAI Global. Across our worldwide operation we manufacture 1 million metres of CIPP lining per year on average, with 75% recycled material in our flagship products. And with over 50 years as the number-one manufacturer of premium, affordable and technologically advanced CIPP liner systems, the first 1971 tube is still in service today.
Bring the Water Main Back Into Compliance
Water main rehabilitation is where a drinking water utility closes the gap between the leakage number it is reporting and the leakage number the regulator is asking for. Trenchless delivery is what makes that possible without a road closure programme the community will not accept.
Explore our InsituMain Pressure technical dataset, or speak to our technical team about your next drinking water main rehabilitation programme.
