MOUNTLAKE TERRACE — Starting Wednesday, you can text to 911 in Snohomish County.

The service is meant only for situations when making a phone call won’t work. Texting 911 has many limitations. It’s slower than a phone call, and location information is not accurate, officials said.

Snohomish County is only the second county in the state to roll out the service. It’s primarily aimed at those with hearing or speech disabilities and for scenarios when making a phone call could be dangerous, such as a domestic-violence kidnapping.

The official 911 message is “Call if you can, text if you can’t.”

People are asked not to send “test” texts to 911. Many such messages have been sent.

The service will continue to evolve with time, said Debbie Grady, the executive director at SNOCOM, the dispatch center based in Mountlake Terrace that serves much of southwest county.

It took months to get it going. After officials saw the first demo of what was possible, SNOCOM supervisor Derek Wilson “immediately said we can and should be doing this,” Grady said Tuesday.

A Snohomish County 911 manager, Laura Caster, has pushed for the service to be made available at the state and regional levels, Grady said.

People who text 911 always should try to include clear information — in their first text — about where they are and also anticipate follow-up questions. They’re also asked to avoid abbreviations and icons, including emotion faces made with symbols. Pictures aren’t accepted at this time. Neither are group texts.

More than 8,700 failed texts to 911 were reported in Washington last year. In addition to Snohomish County, Island, King and Skagit counties are talking about adding the service.

Rikki King: 425-339-3449; rking@heraldnet.com.

What to know

Location information is not accurate.

Texting is not available in all areas.

Texting is not available while phone is on roaming.

A data plan is required to send text messages.

Translation for non-English speakers is not available.

The 911 center cannot control the delivery of the message from the carrier.

Texting is a slower method for reporting emergencies than voice calls, except for those with specific speech and hearing disabilities.

Keep messages brief. Texts are limited to 140 characters.

Do not text and drive.