Pillar guide
Water Networks & Asset Management: Leakage, Pressure, Rehabilitation and AMP8
Treatment works get the attention, but most of the asset value in a water company is buried: hundreds of thousands of kilometres of mains and sewers, much of it older than anyone working on it. This hub covers the engineering of those networks - how leakage is found and modelled, how pressure is managed, how buried pipes are assessed and rehabilitated without digging, how flows are measured to regulatory standard, and how the AMP8 investment period shapes all of it.
Why networks now dominate the capital programme
The 2025-2030 price review period (AMP8) is the largest investment programme the privatised industry has seen, and a large share of it is network work: leakage reduction, mains renewal, storm overflow reduction and sewer capacity. Three physical facts drive the engineering. Leakage scales with pressure by a power law, so pressure management is often the cheapest water a company can produce. Burst rates on ageing cast iron and asbestos cement rise roughly exponentially with time, so the renewal date is an economic optimum, not a failure date. And an open-cut replacement in a city street costs several times a trenchless rehabilitation, so the lining and bursting technologies now carry most of the renewal programme.
The guides in this hub treat each of those problems quantitatively, starting with the physics and ending with worked examples an engineer can repeat on their own network.
Leakage: finding it and modelling it
Leakage is first a measurement problem. The leak detection and repair guide covers minimum night flow analysis, the component-based (BABE) split between background and burst losses, acoustic correlation and the sound-speed physics behind it, transient-based detection, and the economics of active leakage control. The smart water networks guide then covers district metered areas, the FAVAD pressure-leakage relationship, PRV control modes and what a calibrated hydraulic model or digital twin actually adds.
Pipes: assessing and rehabilitating them
The pipe condition assessment guide covers corrosion pit growth, residual strength, burst-rate models and the whole-life-cost timing of renewal. The trenchless rehabilitation guide covers the structural design of cured-in-place liners, pipe bursting, sliplining and spray-applied linings, with the buckling calculation that decides liner thickness.
Flow, compliance and the regulatory frame
Every permit, every overflow setting and every leakage figure rests on a flow measurement. The flow and level measurement guide explains MCERTS certification for effluent flow, the uncertainty budget behind the 8% limit, flumes, weirs and electromagnetic meters, and how flow to full treatment and Formula A are derived. The AMP8 guide explains what the 2024 final determinations commit companies to and how performance commitments, the environment programme and outcome delivery incentives translate into engineering work.
Network engineering overlaps with the treatment topics elsewhere on the site, in particular wastewater management for the works that sewers feed and water quality and compliance for the permits that set flow limits. Where a project needs process design alongside network work, bespoke process design from a practising engineering firm closes the gap.
Guides in this series
- AMP8 AMP8 Explained for Engineers: What the 2025-2030 Price Review Commits the Industry To AMP8 and PR24 for engineers: how Ofwat sets totex and bills, performance commitments and ODIs, the environment…
- MCERTS flow monitoring Flow and Level Measurement at Wastewater Works: MCERTS, Primary Devices, Uncertainty and the Flow Settings They Protect How effluent flow is measured to MCERTS standard: uncertainty budgets, flumes, V-notch and rectangular weirs…
- leak detection water network Leak Detection and Repair: Minimum Night Flow, Acoustic Correlation and the Economics of Finding Water How water network leakage is measured and found: minimum night flow, BABE components, the pressure power law, acoustic…
- water main condition assessment Pipe Condition Assessment and Burst Prediction: From Pit Depth to the Economic Renewal Date How buried water mains deteriorate and fail: corrosion pit growth, residual strength, burst-rate models, condition…
- pressure management water network Smart Water Networks: District Metering, Pressure Management and What a Calibrated Model Really Adds DMA design, the FAVAD pressure-leakage and burst relationships, PRV control modes, sensor placement and hydraulic model…
- trenchless pipe rehabilitation Trenchless Pipe Rehabilitation: Choosing and Designing CIPP, Pipe Bursting and Sliplining Structural design of cured-in-place liners (buckling, ovality, long-term modulus), pipe bursting pull loads, sliplining…
Frequently asked questions
What is AMP8?
AMP8 is the eighth asset management period for water and sewerage companies in England and Wales, running from 1 April 2025 to 31 March 2030. Investment, bills and performance commitments for the period were set by Ofwat in its PR24 final determinations in December 2024.
How is leakage measured on a water network?
Mostly from minimum night flow in district metered areas: the flow entering a DMA in the small hours, after legitimate night use is subtracted, is leakage. Companies then reconcile the DMA totals with a top-down water balance and express the result in megalitres per day, litres per property per day and the Infrastructure Leakage Index.
What is trenchless rehabilitation?
Renewing or structurally repairing a buried pipe without excavating along its length: cured-in-place lining, pipe bursting, sliplining, spray-applied polymer linings and close-fit polyethylene lining. Access is through manholes or short launch pits, so disruption and cost are far below open-cut replacement.
Why does pressure management reduce leakage?
Leak flow rises with pressure, and for most real networks faster than the square-root law of a fixed orifice, because leak openings in plastics and at joints widen as pressure rises. Reducing average pressure, and especially night pressure, cuts both the flow from existing leaks and the rate at which new bursts occur.