The MTA plans to close two Washington Heights subway stations for a year each to ­replace elevators and upgrade safety systems, the agency announced Tuesday.

The 168th and 181st stations on the 1 line will be closed between January 2019 and February 2022 — but not at the same time, officials said.

The renovation schedule will be staggered to minimize service disruptions on the busy line, the agency said.

Both stations are suffering from ­water damage and rot.

The closures are needed to replace the often-broken elevators and replace fire, security and communications systems.

“Replacing these elevators is long overdue and critical for reliable access to these unique ‘deep stations’ ” — some of the farthest below ground in the system.

“We’ve put together a schedule that takes care not to cause unnecessary inconvenience for customers,” said New York City Transit President Andy Byford.

During the three years, M5 bus service through the neighborhood will be increased and there will be free MetroCard transfers between the M3, M4 and M5 bus lines and the subway stations at 157th and 168th streets.

Those transfers will be in addition to standard MetroCard bus-subway transfers.

The closures are part of a broader plan to shore up elevators throughout the system.

Some Washington Heights stations don’t have stairs off the platform level at all, so riders can end up trapped when the lifts suddenly go out of order.