Bright Spots · Water and Sewage · UK and Worldwide

Water and Sewage Bright Spots

Learning from Scottish Water, Severn Trent and PUB Singapore: what the public evidence shows about financing, regulation and system design—and what Joiner, Deming, TOC and TRIZ help us learn.

Syd Stewart · StepChangeAnalysis.com · UK and worldwide · All Bright Spots

UK water and sewage has well-publicised problems. Ofwat’s 2024-25 performance report said pollution incidents were at an unacceptable level and customer satisfaction was at its lowest since the measure began.^[1] But some organisations do better. This page looks at three Bright Spots: Scottish Water (public, UK), Severn Trent (private, England) and PUB Singapore (public, worldwide).

☰ Contents

What the Bright Spots achieved

These are separate snapshots from different reports, not one performance series.

The problem was the system, not just the spills

The English industry faces ageing networks, heavy investment needs, adversarial regulation and, for some companies, high debt. There was an apparent choice: keep bills low, or invest enough to stop the failures. The Bright Spots suggest that choice is partly a result of how the system is financed and overseen.

The contradiction: short-term shareholders, long-term assets

Many private owners want returns that arrive quickly. Water assets—reservoirs, trunk mains, sewers, treatment works—need 30 to 50 years or more to pay back and can last much longer. That is a genuine contradiction: the owner wants fast returns, and the system needs patient investment.

Why the short-term pull matters: dividends, bonuses and high borrowing reward cost cutting and deferred maintenance. The cost of neglect appears years later, in leakage, spills and failing sewers. This is Deming’s constancy of purpose problem: quarterly returns and long-lived infrastructure pull in opposite directions.

TRIZ asks us to resolve the contradiction, not just compromise. Possible resolutions include:

Separation in time: use long-term, lower-return finance for core assets, such as 30-year green bonds, with returns matched to the life of the asset.
Separation by ownership or structure: public, mutual or not-for-profit ownership of network assets, as in Scottish Water and PUB Singapore, or a ring-fenced long-term vehicle that locks in investment commitments.
Change the incentives: link dividends and executive pay to long-run outcomes such as leakage, spills and asset health over ten years, not annual profit.
Match finance to assets: fund long-lived assets with long-term debt so each generation pays for what it uses.

Four things the Bright Spots do differently

1. Plan over decades

PUB plans out to 2065, with NEWater and desalination expected to meet the majority of future demand.^[6] Five-year price-review cycles make that harder in England.

2. Price and finance honestly

PUB recovers full cost through pricing and has raised long-term green bonds tied to named projects such as the Tuas Water Reclamation Plant and the Tuas NEWater Factory. A 30-year green bond is a long-term loan repaid after 30 years, with the money restricted to environmental projects. The term matches the 50+ year life of reservoirs, sewers and treatment plants. The limitation: investors only lend cheaply if they trust the regulation and the issuer’s finances.

3. Measure and report honestly

Severn Trent’s high rate of self-reported pollution incidents suggests a culture where problems are surfaced rather than hidden.^[4] Scottish Water is compared openly against English and Welsh companies, and the regulator publishes where it is below average.^[5]

4. Oversight that helps as well as punishes

See the regulation section below.

At a glance

Bright Spot	What is reported	Improvement principle illustrated
Scottish Water	Best performance ever in 2024/25; leakage down 58% over 15 years; below average on some measures.	Deming: understand variation. Joiner: all one team (public owner, regulator and company aligned).
Severn Trent	Only “industry leading” English company in 2024; best self-reporting of pollution incidents.	Deming: drive out fear. Joiner: a scientific approach through honest data.
PUB Singapore	Closed loop, 2065 planning, full-cost pricing, SGD 800m 30-year green bond.	TOC: elevate the constraint (capital and water supply). TRIZ: turn sewage into a resource.

The framework connections are retrospective interpretations. The published reports do not isolate the effect of each action.

Regulation: fines, or help?

Is the Scottish regulator tough? In a different way from Ofwat. Scottish Water is publicly owned, so a fine would largely move public money from one pocket to another. WICS, the Water Industry Commission for Scotland, compares Scottish Water with English and Welsh companies. Its 2024-25 report says Scottish Water is better than average on supply interruptions, pollution incidents and internal sewer flooding, but below average on leakage reduction, per capita consumption and discharge permit compliance.^[5] A benchmark-driven, collaborative approach may be part of why it works. That is a hypothesis, not a finding.

Deming on regulation: fines do not improve the system. If spills result from underinvestment and a weak system, punishing management encourages people to hide problems, and fear distorts data. Inspecting and fining after the event is waste; the better approach is for regulators to share best practice, use data to separate normal variation from special causes, and look at the whole system.^[8]

Joiner’s levels of change

Brian Joiner’s three levels distinguish fixing the output, fixing the process and fixing the system. See Joiner’s levels of fix.^[7] The classification below is an interpretation, not a claim that any organisation used his terminology.

Level of change	Water and sewage example	Why it fits—and what would make it hold
Level 1 — Fix the output	Repair the worst leaks and clean up individual pollution incidents.	Needed now, but does not prevent recurrence. Permanent firefighting is not a strategy.
Level 2 — Fix the process	Sensor-based leak detection, honest incident reporting, improved overflow monitoring.	Changes how problems are found and handled. Needs skills, data and capacity.
Level 3 — Fix the system	Long-term green finance, full-cost pricing, 50-year planning, oversight based on shared outcomes.	Changes the arrangements that keep creating the problem. Durable only if maintained through changes of leadership and regulation.

The Joiner lesson: use Level 1 to help people affected now, Level 2 to improve how the network is run, and Level 3 to change the conditions that recreate the failures. Joiner also stressed “all one team”: companies, regulators, government and customers working towards a shared aim rather than as adversaries.

Deming: change the system that produces the failures

Deming’s principles include constancy of purpose, driving out fear, cooperation across boundaries and improving the system continually. See Deming’s 14 Points.^[8]

Constancy of purpose: a single long-term aim of safe water, no sewage spills and affordable bills, not five-year cycles.
Drive out fear: do not reward gaming of numbers, and make it safe to report problems.
Understand variation: use control charts on spills, leakage and supply interruptions. React to special causes, not every blip.
Cooperation over competition: share data and methods across companies.
Prevent rather than inspect: invest in the network instead of inspecting and fining afterwards.

The Deming interpretation: a spill is a result of the system to investigate, not only a reason to blame the people running it—except where there is wilful wrongdoing.

Theory of Constraints: find the bottleneck

The Theory of Constraints asks teams to identify the constraint, exploit it, subordinate other activities, elevate capacity and repeat. See Theory of Constraints.^[9]

TOC step	How it could apply to water and sewage
Identify	The binding constraint is probably capital for the network, and the financing and regulatory arrangements that limit it.
Exploit	Spend limited money on the worst leaks, overflows and risks first, not evenly.
Subordinate	Align pricing, regulation and reporting so they support that spending.
Elevate	Raise long-term finance, for example green bonds, as PUB does.
Repeat	Once one bottleneck is fixed, find the next, and judge on outcomes such as clean rivers, not cost cutting or dividends.

The TOC lesson is not “spend more everywhere”. It is to understand what limits improvement and fix that first.

TRIZ: challenge the apparent trade-offs

TRIZ encourages us to question contradictions rather than accept a compromise as inevitable.^[10] There is no evidence that these organisations used TRIZ; the value is in recognising transferable design patterns.

Low bills or high investment? Long-term finance spreads the cost over the life of the asset (Principle 10: Preliminary Action).
Fast shareholder returns or 50-year assets? See the contradiction section above: separate by time or structure, and change the incentives.
Use water or protect rivers? Close the loop, as PUB does with NEWater, so wastewater becomes a resource.
More sewer capacity or less disruption? Reduce flow into sewers with separation and nature-based drainage, rather than only building bigger pipes.
Find leaks or dig up roads? Use sensors and data to find leaks without excavation.
Ideal final result: clean water in, waste out, no spills, at no extra cost.

The contradictions are reduced, not abolished.

Lessons and limits

Plan over decades, not price-review cycles.
Price water at its true cost, with support for those who need it.
Use ring-fenced, long-term finance for named projects.
Tie incentives to outcomes, and reward honest reporting.
Use enforcement for wilful breaches, and collaboration and shared data for system problems.
Do not copy any model blindly: local geography, ownership and politics matter.

The available evidence does not justify declaring the problem solved. It does justify a closer look at what these three do differently.

Explore the wider picture

Bright Spots and Positive Deviance — finding and investigating what works.
Stowhealth: a GP access Bright Spot · Watford: a corridor-care Bright Spot
Joiner’s levels of fix · Deming’s 14 Points · Theory of Constraints · Choosing measures

Test your own improvement

Use the StepChange Analyzer to explore whether a consistently defined outcome series, such as monthly pollution incidents or leakage, shows evidence of a changed performance level. Interpret the signal alongside the intervention history and balancing measures—not as proof of causation on its own.