Graham leaves the position respected by his colleagues.
There are now two elections required.
Firstly, Graham was elected in 2019 as a councillor, so a Hastings byelection will be held to replace him.
Secondly, upon election, he was chosen by his fellow councillors as chairman.
The new chair will be elected before the byelection.
Hinewai Ormsby is eyeing the role, as is Craig Foss and deputy chairman Rick Barker.
Barker, a former Labour MP, would seem to be the strongest candidate with his political acumen and experience.
And with Graham departing mid-term, Barker can argue a "let's not rock the boat'' approach in gathering numbers ahead of the vote.
He also an internal balance of power over Foss, a former National MP whom Barker defeated in the Tukituki seat in 2002, before Foss turned the Tukituki table on Barker in 2005.
Barker, of course, has another chair role on his hands with the West Coast District Health Board. But with DHBs under reconstruction, he is likely to have some free time on his hands.
The less conservative approach would be for Barker to endorse Ormsby and mentor her in aspects of the role. Ormsby's te ao Māori view is invaluable around the council table.
A Māori woman as chair would be an invigorating change.
But with multiple change swirling in the environmental sector, that scenario seems unlikely, and more viable if the chair was being elected at the start of a three-year term - and not mid way through.
A "steady as he goes" approach is more likely from the councillors.
As for the vacant councillor role, if Tom Belford stands, he has a few factors in his favour.
Past experience, and the time honoured political advantage of having a surname that commences with B, near the start of the voting paper.