A joint initiative between the council, Surf Lifesaving Northern Region and Auckland Regional Public Health Service, Safeswim provides real-time data using a modelling system and 120 remote sensors placed around overflow/stormwater systems.
Information includes water quality, safety (tides, swimming conditions), wind speeds and direction, beaches patrolled by surf lifesavers and long-term health warnings.
It also lets people know of other marine hazards such as shark sightings or jellyfish attacks.
McIlroy stresses the programme, launched last summer, will not bring instant improvements in water quality.
For that, the council introduced a water quality targeted rate in June to fund and accelerate improvements across the region. It's a 10-year, $452 million initiative.
Three major projects will upgrade stormwater infrastructure before the America's Cup in 2021: at St Mary's Bay and Masefield Beach, the Daldy St outfall and Picton St stormwater-wastewater separation in the inner city.
"St Mary's Bay will become a Safeswim beach that will have good water quality all the time. At the moment it doesn't during bad weather. The same will apply to Masefield Beach even though it's not used for swimming - it's where a lot of fishing takes place [at the city approaches to the Harbour Bridge]."
In northern Manukau, Takapuna and Red Beach, the council and Watercare have been investigating the stormwater network to trace sources of faecal contamination and find solutions.
The Safe Networks programme, a joint initiative with Watercare, has been scaled up to reduce public health risks at Safeswim-monitored beaches.
"Safe Networks is really what I'd call doing the detailed diagnostics," McIlroy says. "In human terms, it's a bit like putting someone through a CT scanner. We do very detailed forensics looking at the pipe networks, any issues with root penetration or cracks or other issues.
"Even dry weather can cause problems with cracking to the pipes, with the clay soils on the North Shore."
For McIlroy, Safeswim has highlighted the size of Auckland's water quality issues: "But you've got to do it in baby steps.
"We just have to quietly beaver away. There's no silver bullet that's suddenly going to change everything overnight."