The St. Helena City Council agreed 3-2 last week to impose mandatory water restrictions on residents in response to paltry precipitation and a bleak forecast for the rest of the rainy season.

A majority of the council voted to establish a Phase II emergency, even though the council’s agenda only mentioned a discussion of Phase I regulations, which are purely voluntary.

Councilmembers Bonnie Schoch and Sharon Crull disagreed. They said that before the council goes to Phase II, the public should be notified that mandatory measures are being considered.

Phase II requires that customers with even-numbered addresses only water their lawns, plants and vineyards on Tuesday, Thursday and Saturday. Odd-numbered addresses may water only on Wednesday, Friday and Sunday. Watering and irrigation are prohibited on Mondays.

So-called “wasteful usage” of water, including the use of water from hydrants for construction purposes or fire drills, is also prohibited under Phase II.

As of last week, Bell Canyon reservoir, the city’s primary water source, was at 40.6 percent of full capacity. At this time last year the reservoir was 61.6 percent full.

According to the city’s municipal codes, Phase I goes into effect if the level is below 45 percent on Dec. 1. Technically the city was in Phase I throughout 2008, and Tuesday’s agenda item was intended to reiterate the need to conserve.

Those codes call for Phase II to be instituted if Bell Canyon is less than 25 percent on Nov. 1, below 35 percent on Dec. 1, or below 75 percent on June 1. The code also allows Phase II to be established if Phase III conditions — triggered by Bell Canyon falling below 25 percent at any time — appear imminent.

A majority of the council invoked that second provision to declare a Phase II emergency.

Phase I includes voluntary measures that “encourage” customers to reduce their monthly water use by at least 10 percent and “encourage” them to only wash their cars with a quick rinse from a water-efficient hose.

For the full description of Phase I, Phase II and Phase III regulations, go to www.sthelenacity.com, click “Municipal Code,” and read Section 13.04.230-250.