A revision of the town plan is due in a couple of years — it’s required by state law — and it seems likely to cost about $100,000.

Planning and Zoning Director Richard Baldelli told the Planning and Zoning Commission at its Jan. 23 meeting he’d gotten an estimate of $100,000 for a plan revision from Glenn Chalder of Planimetrics, the company that did the last update of what is formally called the town’s Plan of Conservation and Development, or “POCD.”

That estimate isn’t for a completely new plan, but a less ambitious revision, Chairwoman Rebecca Mucchetti told fellow commissioners.

“Our thinking is, we don’t need to start from the ground up and rewrite the document,” she said.

The state requires that town plans be updated every 10 years, and Ridgefield’s plan dates back to 2010.

Mucchetti said the work — and the cost — was spread over two years last time.

Baldelli has approached First Selectman Rudy Marconi about putting an appropriation in the 2018-19 budget, which would allow two years.

Towns that don’t update their plans on time aren’t eligible for state “discretionary spending” — a category that would include state grants the town hopes will help with the planned sewage treatment plant renovation, projected to cost about $42 million.

Marconi’s convinced.

“We have to do that. That’s a ‘have to have,’” he said Monday.

The $100,000 is an estimate — the job goes out to bid, Baldelli said.

“The [POCD] we have now seems to work pretty well,” said commission member Joe Fossi. “It just kills me to spend $100,000 on a document that works quite well.”