under WA land use and zoning codes what is r-22 zoning

There is no standard state-wide designation. You need to contact the appropriate local jurisdiction for their definition. If the property is within the city limits of Vancouver, the city code applies. Otherwise, the Clark County Code. You should probably start with their websites, which include links to zoning codes and definitions:

http://www.cityofvancouver.us/MunicipalCode.asp?menuid=10462&submenuID=10478&title=title_20&vmc=index.html

http://www.clark.wa.gov/commdev/title40N.html

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It is correct that there is no standard zoning throughout the state and that you would have to look at the city or county zoning codes to be sure. Generally, however, "R" refers to rural and the number, in this case 22, refers to the permitted density. So it would be typical for R-22 to refer to rural 22 acre lot zoning.

Definitions differ from town to town and city to city and there is no standard zoning definition for R-22. Phone your zoning administrator to provide you with the actual definition for the place you are asking about.

Good luck.