Charles Ellicott Commentary Numbers 18:31

"And ye shall eat it in every place, ye and your households: for it is your reward in return for your service in the tent of meeting." — Numbers 18:31 (ASV)

And you shall eat it in every place.— When the tenth which was due to the priests had been duly paid, the remainder of the tithe received from the people became the rightful portion of the Levites, as their ordinary means of subsistence, and might be eaten by them in every place, not being subject to the restrictions laid upon the priests in regard to the place in which the holy things were to be eaten. (See Numbers 5:10.)