I have parcel layer and table of water meters, they are related. Now I want to symbolize parcels based on water meter district ID it is just two digits. I was able to do so by joining tables, but if there is any other way that will eliminate the need to use join and use just relate, I am using ArcMap 10.5?
Join is your only option for symbolizing based on a field in a related table. The only other option is to join the related table and calculate the ID into a field stored on the target feature class so you can symbolize directly from the feature class. If the relationship is a one-to-many or many-to-many relationship then you could export the join to a new feature class to create a feature for each record in the related table. Symbology cannot be set up to use a relate.
See this thread: https://community.esri.com/thread/164994 - this includes instructions on how to use definition queries to symbolize based on records in a related table
