Dirty Lines That Form Around the Sides of a Bath

This page is the CodyCross answer for the clue below from Life on Wheels, Group 1795, Puzzle 2 (Wear a Helmet).

Question is: Dirty Lines That Form Around the Sides of a Bath

and the answer is: TIDEMARKS

Word Meaning:

TIDEMARKS — plural of tidemark

Definitions from Wiktionary.