The Sewer Key is one of the most important hidden items in Sell Lemons because it unlocks a secret area containing the Cosmic Cash Vine. Once unlocked, this special vine can be harvested every four hours for extra money, making it a valuable upgrade for anyone actively playing the game.
The process is not difficult, but the sewer maze can be confusing because several colored levers open and close different pathways. If you pull the wrong lever at the wrong time, some routes become inaccessible. The easiest approach is simply following the lever order below exactly.
How to Get Sewer Key in Sell Lemons (Cosmic Farmer Badge)
Head into the sewers and locate the locked gate that requires the Sewer Key.
This is the area you’ll eventually unlock after finding the key.
Before you can reach it, you’ll need to manipulate several colored levers hidden throughout the sewer system.
The lever sequence is:
- Blue Lever
- Red Lever
- Green Lever
- Red Lever (again)
- Blue Lever (again)
- Purple Lever
- Red Lever (again)
- Sewer Key
The order matters, so don’t skip ahead.
Step 1: Pull the Blue Lever
Enter the sewer and follow the route marked by the green-colored signage.
Continue moving deeper into the tunnels until you eventually reach the Blue Lever hidden near the end of the path.
Pull the Blue Lever.
After activating it, resetting your character is actually faster than running all the way back through the maze.
Step 2: Pull the Red Lever
Return to the sewer entrance.
Near the locked Sewer Key gate is a short side passage leading directly to the Red Lever.
This one is much easier to find than the Blue Lever.
Pull the Red Lever.
Unlike the previous step, there’s no need to reset immediately because the next objective is relatively close.
Step 3: Pull the Green Lever
After leaving the Red Lever area, head toward the next sewer passage.
When entering this section, remember one important detail:
Turn left.
Many players accidentally turn right and end up in the wrong section of the maze.
Continue through the corridors until you eventually reach a long hallway leading toward the Green Lever chamber.
Pull the Green Lever when you find it.
Once activated, reset your character again to save time.
Step 4: Return to the Red Lever
This is where many players get confused.
You already activated the Red Lever earlier, but now you need to return and interact with it again.
The sewer puzzle works by opening and closing different doors depending on lever states.
Go back to the Red Lever and switch it back.
This changes the layout of the sewer system and grants access to new routes that were previously blocked.
Step 5: Return to the Blue Lever
After changing the Red Lever, travel back through the sewer network until you reach the Blue Lever again.
This time, switch it back as well.
Think of this step as resetting part of the puzzle so additional pathways become available.
Once you’ve done that, reset your character.
Step 6: Find the Purple Lever
Head back into the sewer and follow the route leading toward the orange-colored section of the tunnels.
This area eventually leads to the Purple Lever.
The path is slightly longer than the Red Lever route, but much easier than the Green Lever section.
Once you reach the Purple Lever, pull it.
With the Purple Lever activated, you’re almost finished.
Reset one final time.
Step 7: Activate the Red Lever Again
Yes, the Red Lever is required one more time.
Return to the Red Lever location and pull it.
This final adjustment opens the route leading directly to the Sewer Key.
Now you can finally enter the newly accessible section of the maze.
Finding the Sewer Key
After activating the Red Lever, enter the area that has just opened.
Follow the tunnel system through several corridors until you reach a section marked with green-colored walls.
Continue forward.
Eventually you’ll arrive at a junction.
Take the right path.
Soon afterward you’ll notice a small blue-colored area.
Enter the blue section and check the first chamber.
Inside you’ll find the Sewer Key waiting to be collected.
Pick it up.
Unlocking the Secret Sewer Room
With the Sewer Key in your inventory, return to the locked gate near the sewer entrance.
Interact with the door and use the key.
The gate will permanently unlock, granting access to the hidden Cosmic Cash Vine area.