Developing a Non- Revenue Water Strategy Richard Taylor, Thomas Civil & Environmental Consultants h PWC’15 September 2015

Firstly, how do we define Non-Revenue Water? Let’s look at the IWA Standard Water Balance

The Danger of Relying on Percentages Paradise Island

The Danger of Relying on Percentages Paradise Island At Normal Demand NRW = 30%

The Danger of Relying on Percentages Paradise Island With Increased Demand NRW = 25%

The Danger of Relying on Percentages Paradise Island With Reduced Demand NRW = 37.5%

The Danger of Relying on Percentages NRW 30 % NRW 25 % NRW 37.5 % But NRW Volume (including Real Losses) are Unchanged Don’t be fooled – Be aware Paradise Island

The Danger of Relying on Percentages NRW 30 % NRW 25 % NRW 37.5 % Paradise Island Best Performance Indicators for Real Losses Litres/conn/day (urban areas) or m3/km main/day (rural areas), and Infrastructure Leakage Index (ILI)

Developing a NRW Strategy Where do we start? Key Objective #1 Reliably measure System Input Volume It is essential that the volume of water supplied into the water network is reliably measured

Developing a NRW Strategy Key Objective #1 Continued Reliably measure System Input Volume Is a suitably sized meter installed? Is it installed correctly? Is ‘air’ an issue? Is data being accurately recorded?

Developing a NRW Strategy Key Objective #2 Maximise Revenue Water Are meters installed at the property boundary? Are meters recording water use accurately? Are water bills correct?

Developing a NRW Strategy Key Objective #2 Continued Maximise Revenue Water Have a plan to meter any ‘unmetered’ connections Is all water utility and public water use metered and billed? Parks, toilets etc. Is water tanker use metered and billed?

Developing a NRW Strategy Key Objective #3 Minimise Apparent Losses Unauthorised Consumption - Have a plan to check for illegal connections. Reward meter readers? Compare aerial photos with meter locations (desktop study)? Door to door check?

Developing a NRW Strategy Key Objective #3 Continued Minimise Apparent Losses Customer Meter Under-registration – Check meter accuracy – use a 20 litre container? In-line meter calibration check? Bench tests?

Developing a NRW Strategy Key Objective #4 Reduce Real Losses These include: Leakage on mains Leakage and overflows at reservoirs Leakage on service connections up to the street/property boundary (meter location)

Developing a NRW Strategy Key Objective #4 Cont’d Reduce Real Losses The Four Complementary Leakage Management Activities

Developing a NRW Strategy Key Objective #4 Cont’d Reduce Real Losses 1. Speed and quality of repairs

Leak Run Time Awareness Leak Volume Loss = (A+ L+R ) Time x Flow Rate LEAK RUN TIME FLOW RATE A L R RUN TIME = *Awareness + Location + Repair

Bursts with high flow rates don’t produce the largest volumes of Real Losses! Run time is a key factor. m3 / day 75 reported mains burst 82.5 m3 1.1 Days m3 / day 16 Days reported service connection burst 400 m3 25 R L A In the past, we spent a lot of time locating burst mains and feeling satisfied when they were repaired. Recent research has shown (in the top diagram) that whilst the average burst main runs at 75m3/day, it is repaired after only 1.1days, losing 82.5m3 in total. The Water Supplier’s communication pipe has a lower flow rate at 25m3/day but runs for 16 days losing 400m3 . Worst of all is the leak inside the customers boundary which loses 1150m3, 14 times more than the average burst main. It is therefore very important that the leakage practitioner understands the condition of his distribution system and where the leaks might occur. L m3 / day unreported service connection burst > 4500 m3 25 6 months? R A 19

It’s OK. It’s been like that for weeks. THIS RESULTS IN VERY HIGH WATER LOSS

I’ll ring or text the water people so it will be fixed straight away. THIS IS THE PATH TO LOW WATER LOSSES

The volume leaked: Say 7 litres/min x 60 x 24 = 10,080 litres/day, = 10m3/day = 70m3/week = 3,680m3/year The leak has to be repaired some time. Delaying doesn’t save any money, it costs money and causes high leakage (and high NRW) The cost (at NZ$.40/m3) = $4/day = $28/week, = $1,450/year

I think a Public Relations Plan may be required as part of a NRW Strategy so that the public report faults straight away – And it will be important that the utility follow up by: Fixing leaks promptly & Fixing leaks properly

Developing a NRW Strategy Key Objective #4 Cont’d Reduce Real Losses 2. Pipe materials management, selection, installation, maintenance, renewal

Take Note: Leakage from watermains is generally not the key issue, leakage from service connections is

Developing a NRW Strategy Key Objective #4 Cont’d Reduce Real Losses 3. Active Leakage Control

Active Leakage Control Active Leakage Control (ALC) is the only way to locate ‘Unreported’ leaks.

Active Leakage Control

Sectorizing a Water Supply Network

Monitoring of Minimum Night Flows into a Network or Zone Monitor Low Flows at Night

Developing a NRW Strategy Key Objective #4 Cont’d Reduce Real Losses 4. Pressure Management

Relationship Between System Pressure & Losses N1 varies 0.5 - 2.5 depending mainly on pipe material & existing leakage rates

Example of Pressure Management Reducing Real Losses (and Demand) Water pressure reduced by 30% 33% Reduction in Minimum Night Flowrate

Flow and Pressure Control Installation

Developing a NRW Strategy – To Recap Key Objective #1 Reliably measure System Input Volume Key Objective #2 Maximise Revenue Water

Developing a NRW Strategy – To Recap Key Objective #3 Minimise Apparent Losses (Unauthorised consumption and Customer Meter Under- registration)

Developing a NRW Strategy – To Recap Key Objective #4 Reduce Real Losses

Why Reduce Non-Revenue Water? Water Scarcity Ex Harrison Mutikanga - AFRICA Absolute scarcity (insufficient quantity at the source – exacerbated by climate change) Economic scarcity (financial constraints to expand infrastructure to meet increasing demand; poor planning & demand forecasting) Scarcity from poor management (high leakage & wastage, poor O & M practices, governance issues – corruption, etc.) Other good reasons….

Why Reduce Non-Revenue Water? HAPPY CUSTOMERS HAPPY WATER ENGINEERS HAPPY WATER BOSSES

Thank you Any questions?