The state-level rules every owner and walker in Maine should know. Local leash lengths, licensing and off-leash rules are set by each city — find those on the city pages below.
Maine defines its dog strict liability by location — off the owner's premises, the owner or keeper is strictly liable — which is exactly the dog-walking scenario.
Maine (7 M.R.S. § 3961) has one of the most walker-relevant structures in the country because its strict liability is defined by location. Off the owner's or keeper's premises (§ 3961(2)), the owner or keeper is strictly liable for a dog injuring a person — no negligence, prior history, or knowledge needed; this is the classic out-on-a-walk scenario. On the premises (§ 3961(1)), the victim must prove negligence. Maine rejected the one-bite rule in 2001, and keeper is defined as a person in possession or control of a dog — so a walker is a keeper and a named strictly-liable party off-premises. Since walking a client's dog is by definition off the owner's premises, the strict-liability track is the default for the walking scenario.
Comparative fault is limited and victim-favorable: a victim's fault cannot reduce damages unless it exceeds the owner's or keeper's. The statute covers property damage and injuries to other pets. Dangerous-dog orders can require $100,000 insurance and treble damages for non-compliance (§ 3952-A). The personal-injury limit is an unusually long six years.
This is general information about Maine law, not legal advice. Confirm current rules with the official state and municipal sources.