Businesses, homeowners, and renters in Washington are responsible for maintaining their premises to avoid injury to guests or others invited to the business or home. This means businesses, homeowners and renters must keep sidewalks (and parking lots for businesses) free of snow and ice hazards, and must make sure any water or ice tracked inside do not pose hazards that might cause someone to slip, fall and be injured. Washington has pattern jury instructions (WPI), and it is helpful to look at the pattern instruction on a duty of a business to maintain a safe premises.
(WPI) 120.07 Liability to Business or Public Invitee—Condition of Premises:
An [owner or occupier of premises] is liable for any [physical] injuries to its [business invitees, public invitees, or customers] caused by a condition on the premises if the [owner or occupier]:
(a) knows of the condition or fails to exercise ordinary care to discover the condition, and should realize that it involves an unreasonable risk of harm to such [business invitees, public invitees, or customers];
(b) should expect that they will not discover or realize the danger, or will fail to protect themselves against it; and
(c) fails to exercise ordinary care to protect them against the danger.
Homeowners have similar legal responsibilities to maintain their home and property (including sidewalks around the home) so that they are safe. Most cities have specific codes that tell homeowners that they must maintain sidewalks around their home free of ice, snow and other hazards. For example, Seattle Municipal Code states that “property owners are responsible for maintaining sidewalks adjacent to their property.” Seattle homeowners should read this so that they understand their duties:
So what should a homeowner or business do? If you know a storm is coming, plan ahead and make sure you keep all sidewalks (and parking areas for businesses) around your home or building, safe and clear of ice, snow, or other hazards. Make sure you have mats inside doorways to help reduced tracked water into your business. Be sure to carefully monitor your premises, and if there is a hazard (like tracked water that gets on the floor) warn customers or guests about the hazard. If you lease your business location, your landlord may provide snow and ice removal. If you rent a home, you are not relieved of responsibility to keep your premises safe. 
Local Seattle radio station KUOW did a great report on January 15, 2020, which explains that homeowners have an obligation to clear snow and ice from sidewalks around their home:
https://www.kuow.org/stories/did-you-shovel-your-sidewalk-you-were-supposed-to
Anyone injured due to any unsafe condition at a home or business may be eligible to use any medical payments coverage available to the business under any commercial liability policy (most provide for $2,500 or $5,000 for medical expenses), and may also present a liability claim against the homeowner or business for any injuries or damages. A good personal injury attorney will be able to answer questions about claims that may be made for injuries due to any unsafe condition at a home or business.