Prevention is better than cure in tackling UK water leakage rates

How does the UK move towards a preventative leakage strategy that isn’t based on averages and assumptions? Joe Sanders and Michael Butler report

05 Oct 2020

This year marks the start of the journey the UK water companies have agreed with their regulators to deliver ambitious leakage targets. Company business plans outline investments to deliver more than 800 megalitres per day (Ml/d) of new capacity and demand reductions by 2025, through short-term supply options, leakage reductions, and water-efficiency programmes.

The new regulatory targets were always a challenge, never mind the flooding across the UK in February, the onset of the COVID-19 pandemic, and this summer’s drought-like conditions in some parts of the country.

Water companies are seeking the cheapest ways to reduce or maintain leakage levels. But achieving this may not just be a question of using novel ways to find more leaks or fix them faster – it’s about not letting leaks occur in the first place. Prevention is better than cure.

To understand how and where to make efficiency gains in leakage, RPS uses a methodology based on the life of a leak, broken down into four parts – prevent, predict, detect and repair – to review each activity that goes into fixing a leak. 

The most efficient way to reduce leakage is to prevent it occurring in the first place. The ability to predict where leakage is most likely helps to optimise resources. And using the right technique to detect leaks as early as possible supports fast and efficient repair, helping to avoid leakage.

Looking at the life of a leak frames the challenge in terms of real-life leaks; how must we respond when a leak occurs? How do leaks build up to impact the holistic cost of leakage programmes?

If you prevent a leak happening, it doesn’t affect your leakage calculation. You don’t have to spend the time finding the leak or the money fixing it and reinstating the site of excavation. So why hasn’t this been the water companies’ operating model since privatisation?

The answer comprises three main points: the economic level of the water sector’s leakage policies over the past few decades, the belief that leakage is an operational-cost problem and the perceived cost of the end product.

Let’s consider each point, to examine why water companies are more reactive than proactive when it comes to tackling leaks, and how some new initiatives could drive proactive investment.

Economic leakage policies

Since privatisation in the late 1980s, the premise of leakage targets has been that the cost to find and fix the leaks should be lower than the cost of water production. And so the water industry sees little advantage in improving efficiency and is constrained by limited innovation.

However, determining leakage targets has evolved considerably; the most recent price review effectively removed the economic level of leakage from target setting. Most companies have adopted Ofwat’s suggested reduction which, combined with limited additional funds to meet these targets, has been the biggest shake-up in leakage-management up for some time.

Operational costs

Often leakage is deemed to be a problem of operating expenditure that requires more people to find and fix leaks to improve performance. This is inefficient and supports short-term solutions to address the problem – it does not bring the benefits of addressing the root cause, as several water companies now are.

Having learned that full asset renewal or extensive pressure management leads to lower leakage levels, these companies are making these strategies central to their leakage-reduction plans.

Water is cheap

Water is significantly cheaper than other household utilities. The average water bill is £186 a year, compared to gas at £610 and electricity at £680. This has given water firms limited funds to invest in addressing leakage; most have therefore favoured solutions with immediate returns over those that deliver long-term benefit.

Post privatisation, many customers feel service has worsened as dividends have increased. Water-company initiatives to urge customers to consider the environmental cost over the economic cost of water could move the debate, but water has not yet had its Blue Planet moment.

So, how can water companies meet the AMP7 challenges and how can they develop more preventive leakage strategies?

Using data to target proactive investment

High-quality data from the network and operations teams will enable water firms to spot leakage – and rectify it faster. A spike in stop-tap failures might highlight a faulty batch in one area. An increase in mains and customer-side failures points to the pressure being too high in another.

Too often, leakage strategy is based on averages and assumptions; a burst main is approximately 1m3/hr; a district meter area takes 4 weeks to survey. These averages and approximations make it harder to identify where to invest and what benefits this will deliver.

However, it is easy to collect much of this data without reducing efficiency. Mobile apps can track how long it takes to survey an area, and simple analytics provide the flow rate for failures and the speed at which they grow.

Using this data will help leakage-optimisation engineers to know what corrective action to take, using the exact results from that area.

Pressure control

Pressure control is probably the most widely used preventive measure for reducing an area’s leakage. If pressure management is designed, operated and maintained correctly, it is very effective in reducing existing leakage and addressing its root cause.

Pressurised water will find the weak spots in the network and the failure under pressure will cause the leaks we see – lower the force that the water can assert on the weak spot (by reducing the pressure) and you will cut the occurrences of leaks on your network.

Pressure-controlling systems have advanced, but customers are often not keen on them; the shower is less powerful, the paddling pool takes longer to fill. The debate continues about the environmental impacts of water use, but there is an irrefutable argument for these measures to become part of a new normal, to preserve our natural resources for future generations.

It’s not just about pressure reduction; identifying pressure transients and tackling root causes removes pressure spikes and shocks to the network, such as from pump start/stop and erratic use by large customers that cause weaknesses that lead to leaks.

Additional benefits

Most, if not all, interventions to reduce leakage benefit other regulatory drivers. Water meters show high usage and customer leakage and support targeted water-efficiency campaigns to persuade customers to use less water.

Upgrading the mains delivers assets that may last 160 years, reducing interruptions to supply. Historically these benefits rarely made it into business cases for leakage-driven schemes; the pressure of AMP7 on cost, efficiency and performance means now is the time to examine all these benefits in full.

Now is the time for preventive long-term leakage solutions. The AMP7 targets and the predicted AMP8 targets mean short-term fixes are no longer appropriate to tackle leakage rates. It will take targeted investment, using improved data, to meet these tough new targets.

 

This article was first published in the October 2020 edition of The Environment Magazine, CIWEM.

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The most efficient way to reduce leakage is to prevent it occurring in the first place. The ability to predict where leakage is most likely helps to optimise resources. And using the right technique to detect leaks as early as possible supports fast and efficient repair, helping to avoid leakage.

Michael Butler

Technical Manager

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