It's the law that you have to keep your guns secured from unauthorized use.

See https://app.leg.wa.gov/rcw/default.aspx?cite=9.41.360

One little tidbit from this page on app.leg.wa.gov goes as follows:

unsafe storage of a firearm in the first degree is a class C felony punishable according to chapter

Make sure no one else can access your gun(s).

Free Gun Locks

It’s imperative to store your guns so that no one else can access them. This is a link to a gun cabinet I purchased recently. It’s very affordable and large enough for a whole pile of guns. https://www.walmart.com/ip/Sentinel-18-Gun-Fully-Convertible-Cabinet-Black/19216477

Whether you have one or many guns, it’s important to keep them under lock and key. A quick Internet search for gun locks, or gun safes will yield a wide array of options.