The Andris Sewer is just W. of the town by the West Gate, on the way to the Public Stables on that side. Inside, many rats circle the Ladder, similar to Mirith's Mirith Sewer, and occasionally Marali's Marali Sewer.
A series of loops and long trenches in the sludge maintain obstacles against being constantly-swarmed, while the 8 Chests provide plenty of danger and their own loot.
Similar to Marali's, Andris' provides red crystals, which can be useful in returning to Andris during the Blue Moon Festival, for example. As well as to the Red Portal for nearby The Tower, a source of quick exit if stuck or abilities are limited. This is like one Dungeon bailing-out another.. though can Sewers bail-out anything so distant?
Also handy for the Festival, any Bundle of Kindling can be used for cooking the whole way, through, and this Sewer has plenty.
Finally, like Marali, it even has a few bottles of Poison. Far fewer, however.