Sewers are the gimmicks of Steam Ages. They are holes found on the lawn. They either make toxic steam or help transport zombies. Flat-shroom was designed to block these, but due to a coding error, this is currently not possible. The Lotus Root also acts as counter to toxic steam, and is thus the only option.
Variants of sewers
Sewers that give off steam first appear on Day 1. They start being covered by manholes, being harmless. However, later they fling their manhole out of the lawn to give off steam in a 3x3 area, damaging plants continuously. A Flat-shroom being planted on it can only last a limited time as the steam will eventually destroy it, or fling the Flat-shroom out.
Sewers that transport zombies act much like Lost Guide Zombie's secret doors, but zombies are transported slower and are able to appear in other lanes. Only small-to-medium sized zombies can be transported, while Gargantuars and machines ignore them. Being able to be planted on sewers, Flat-shroom (functioning correctly) acts as a blocker preventing these zombies from entering and exiting the sewer for a limited time, until it gets eaten.
- Due to a coding error, Flat-shroom can still be eaten by zombies that are on the lawn in addition to the aforementioned error.
- Even if the player chooses Jackfruit to block the sewers which transport the zombies, the plant will not block them.