The towns of Essex and Jericho plan to re-address all Old Pump Road properties to prevent another mix-up like last month’s that saw emergency responders arrive at the wrong house.

Most of Old Pump Road falls within the town of Essex, but a small section of the 1.8-mile road, just before it meets Route 15, is in Jericho. Because of that, some residents of the neighboring municipalities have identical numbers, and a recent emergency call found Essex Rescue personnel arriving at what they thought was the right house. Turns out, they were in the wrong town.

Hearing this, the state asked the two towns to remedy the problem before another issue arises. Staff told the selectboard earlier this month if members chose not to follow through with the re-addressing plan, the town would need to assume liability for all future incidents involving these mix-ups.

In the name of fairness, staff is now working with Jericho and the state to completely renumber the road so “everybody hurts the same,” deputy town manager Greg Duggan said.

Jericho and Essex use a 50-foot numbering system for Old Pump Road, meaning houses numbered 100 are about a mile down the road, according to Tyler Hermanson, a Geographic Information System specialist with the state.

The state standard, meanwhile, uses a 1,000-per-mile standard, so if your address is, for example, 1000 John Smith Way, you’re a mile down on the right side of the road.

Hermanson said that method provides more numbers to choose from and limits the chance for duplicates. He said about 80 percent of the state now uses that system, most of which adopted it decades ago when 911 first came on board in Vermont. Then, towns were given a choice: Follow the state standard or keep using whatever increment the town already had in place.

Essex and Jericho chose the status quo. But the real problem here is the two towns numbered the road from its perceived start. That means starting from Route 15 in Jericho, houses along Old Pump Road begin with 1 and go to 94, while starting out in Essex finds houses that begin with 4 and end at 92.

Hermanson said there’s four or five Old Pump Road houses that now have the same number in towns. The solution in some towns facing such a scenario is to fiddle with the impacted house numbers, but many times most numbers are already taken.

The ideal scenario for any road is a continuous numbering system, Hermanson said. He and the state often help facilitate re-addressing projects, and in recent years have modified entire towns. For example, Alburgh re-addressed about 90 percent of its business and residential properties last year, resulting in changes to about 1,800 locations, Hermanson said.

The impacted properties aren’t as many here: Jericho has about 30 homes on Old Pump Road, and Essex has 18 with an additional three now in construction.

The selectboard authorized the town to continuing working on the project and start alerting homeowners of the expected changes. Residents will have six to eight weeks to change their mailing address before the new system goes into effect.

Selectboard chairman Max Levy asked if there were any other roads in town with a similar problem. Staff said they would find out.

“If there are,” Levy said, “let’s do those before there’s a situation.”