Affinity Water’s neutrality trial slashes consumption levels

Affinity Water has reported success from its water neutrality pilot scheme that focused on behaviour change and interventions to cut home and non-household usage.

The amount of water used in the area fell from 246,000 litres daily to 238,000 litres, which left 8,000 litres more water in the environment each day than previously.

The trial, named Project Zero, received £2.9 million from the Ofwat innovation fund in 2022 to trial the impacts of behavioural change and water efficiency devices in new homes.

A new development called Bidwell West was selected in a water-stressed region, adjacent to Luton with the ambition to be the first water-neutral housing development in the world.

Affinity’s water neutrality engineering manager, Julian Webster, said: “We’ve got some challenges on the project, but we are seeing fantastic results based just on behaviour change without actually impacting developers building.”

Initial results show usage dropped by 8,000 litres daily to 238,000 litres after residents were encouraged to sign up to a pledge campaign to use water efficiently in their homes.

Speaking at the WWT Innovation and smart water conference, Webster explained that the original pitch had adapted, with the number of homes included scaled back from 3,000 to 2,000 participant households.

Secondly, the pilot intended to compare impacts of behavioural change compared in some locations with adding water saving devices in other homes, and the combination of both approaches in others.

So far, Affinity has only rolled out the behaviour change techniques. This is due to stringent rules to ensure high drinking water quality is maintained, non-potable water cannot be supplied even for non-drinking use.

“There have been struggles to engage developers, but a bigger blocker has been regulation,” Webster explained.  “Under the water supply regulation act we cannot supply non-potable water, we’re governed to supply wholesome water for sanitary and irrigation purposes, which would be where we’re looking to supply reuse technology.”

He said there was however a “gap” in legislation to enact private supply regulations to potentially deliver these but suggested the experience of water wholesalers being involved to maintain quality would be advantageous.

Earlier this month, a government-backed proposal to address water scarcity in the Cambridge area and enable homebuilding was granted £4.5 million to get water efficiency devices installed and establish an offsetting scheme.

Affinity learnt the simpler the messaging, the more effective it has been. Residents were invited to pledge to up to eight water saving initiatives ranging from using a watering can instead of a garden hose, taking shorter shows or turning the tap off when brushing teeth, as well as opting for eco-mode on dishwashers and washing machines.

An awareness campaign ran alongside the pledges sharing very localised information about water usage and impacts to the environment. Per capita consumption reduced to 105 litres daily following the campaign, which ran between April and August last year. This is down from an average of 145 litres PCC.

“It’s really positive to see we are below the 125 or 110 targets being discussed for new build homes,” Webster reflected.

The 382 homes that signed up to at least one pledge saved an average of 33 litres daily, homes that did not sign up to a pledge also saved 23 litres daily.

Affinity’s water resource management planning (WRMP) for the coming decades includes water neutrality as an enabler to support the looming supply deficit of 4,000 megalitres by the middle of this century.

Webster said Affinity alone could have saved roughly 72 megalitres of water over 10 years from the 75,000 new homes proposed in its region if these principles had been applied: “If,” he said, “we can start delivering water neutrality as the norm.”

Customers in Bidwell West have their water supplied via new appointments and variation (NAV) supplier Independent Water Networks, which Affinity is the wholesale provider to. Affinity led the innovation project with behaviour change support from Grapevine.

The intention, as with other schemes funded through the Ofwat Discovery Challenge in its innovation fund, is for Bidwell to act as a blueprint for other potential water neutrality projects.