John Gill Commentary Nehemiah 3:26

"(Now the Nethinim dwelt in Ophel, unto the place over against the water gate toward the east, and the tower that standeth out.)" — Nehemiah 3:26 (ASV)

Moreover, the Nethinims dwelt in Ophel
An high tower upon the wait, in this part of it, see (2 Chronicles 27:3) , these were servants to the Levites, and repaired here, where their dwellings were:

unto the place over against the water gate toward the east :
and as one part of their work was to fetch water for the temple, they were here very properly situated; it led to the king's garden, the valley of Jehoshaphat, and from thence a plain way to Bethany:

and the tower that lieth out ;
from the wall.