Unlocking the Sewer Tunnels in Atomfall: A Complete Guide

In Atomfall, accessing the Sewer Tunnels in the first region is crucial for progressing in the game. While the initial key opens the tunnel entrance, a second key is required for the Maintenance access door within—making it essential to find both.

How to Begin Your Search for the Sewer Tunnels Key

To unlock the Sewer Tunnels door in Atomfall, you must identify a specific shopkeeper willing to provide the key—for a price. But how do you go about finding this elusive vendor?

In northwestern Slatten Dale, you’ll encounter a locked door that leads to the Sewer Tunnels. You can find it at coordinates 24.9E, 78.1N. But what about the key?

Concrete Shelter location on map — Screenshot by Moyens I/O

Finding the Key to the Sewer Tunnels in Atomfall

The key is held by a merchant in Slatten Dale who will trade it to you if you have the right items. Next to the door, there’s a note stating, “Yours for a fair price!” This note indicates that the trader, Molly Jowett, possesses the key for the concrete shelter leading to the tunnels. She advises that interested individuals should locate her “down the hill.”

Atomfall - Sewer Tunnel key location - Note for key — Screenshot by Moyens I/O

Exit the bunker and travel northeast along the path until you see smoke coming from a small shelter in a clearing.

Atomfall - Sewer Tunnel key location - Molly's camp — Screenshot by Moyens I/O

This location is Molly’s Trader Camp, indicated on your map at 26.3E, 79.0N. Speak with Molly until you find the Barter option.

Molly's camp on the map — Screenshot by Moyens I/O

Select Barter to browse Molly’s inventory for the key. You should see the Concrete Shelter Key listed among her items.

Optimal Items to Trade for the Key

Molly, like other traders in Atomfall, employs a Barter system, exchanging items without the use of cash. It’s important to note that some traders prefer certain goods over others, and Molly is no exception. She’s interested in specific items for the key. Check the “To Give” section in the Barter menu to discover these preferences.

Atomfall - Sewer Tunnel key location - Trader value — Screenshot by Moyens I/O

Here are some of Molly’s preferred items listed from Low to High:

Bandages (Low)
Tea (Low)
Cricket Bat (Medium)
Rifle Ammo (High)
First Aid Kit (High)
Painkillers (High)

It’s important to note that a single high-value item may not suffice for the key; combine items to achieve a favorable trade balance. This is also a great opportunity to offload excess inventory.

Once you obtain the key, return to the Concrete Shelter and unlock the previously locked door. However, be aware that a second locked door exists in the sewer tunnels that will require another key.

Where to Find the Sewer Tunnel Key in Atomfall

In the Sewer Tunnels, follow the Maintenance signs to arrive at the locked Maintenance room. To access it, you’ll need the Sewer Tunnel Key. Although it may seem like the key is out of reach, it’s actually closer than you think—located in the nearby locked Control Room.

Atomfall - Sewer Tunnel key location - Maintenance Door — Screenshot by Moyens I/O

To find the Sewer Tunnel Key, you must first access the nearby Control Room through the Casterfell Woods region. Look for signs indicating the Casterfell Woods in the Sewer Tunnels.

Follow the signs to a gated door at the north end of the sewer tunnel. The good news: this door is unlocked.

Atomfall - Sewer Tunnel key location - Casterfell Woods directions — Screenshot by Moyens I/O

To locate the room containing the key, you must access the elevated highway running through Casterfell Woods.

To reach the road quickly, go north from the Sewer Tunnel exit. Walk a short distance and then head east to go under the road.

Accessing elevated highway in Casterfell Woods — Screenshot by Moyens I/O

Once you reach the road, hug the rocky wall to your right and head west. Climb the short hill that leads to two ladders. Use them to reach the road and proceed south while avoiding bandits until you arrive at the closed tunnel entrance.

Navigating to the ladders in Casterfell Woods — Screenshot by Moyens I/O

To the left of the southern tunnel entrance, you’ll find another concrete shelter.

Concrete Shelter location for Control Room — Screenshot by Moyens I/O

Enter to access the Control Room, and search the area near a desk for a corpse.

Locating the Sewer Tunnel Key in the Control Room — Screenshot by Moyens I/O

Loot the body to obtain the Sewer Tunnel Key along with a note. With the key in hand, return to the Maintenance Room to unlock the door.

After entering, navigate through the gap between crates and tipped shelves to explore the back area.

Exploring the back area of the Sewer Tunnels — Screenshot by Moyens I/O

Inside, you’ll discover various resources including cloth, ammo, string, and more. Don’t miss the B.A.R.D. Crate on the ground—it contains items and a Training Stimulant.

B.A.R.D. Crate in the Sewer Tunnels — Screenshot by Moyens I/O

With all this completed, you’ve successfully navigated the Sewer Tunnels and are ready to face the next mystery in Atomfall.

Frequently Asked Questions (FAQ)

1. How do I unlock the Sewer Tunnels in Atomfall?

To unlock the Sewer Tunnels, you need to find Molly Jowett, who will trade you the key for specific items.

2. Where can I find Molly in Atomfall?

Molly is located down the hill from the locked door in northwestern Slatten Dale, specifically at her Trader Camp.

3. What items are best to trade with Molly?

Molly prefers items like Rifle Ammo, Painkillers, and First Aid Kits. Combine lower-value items if necessary to secure the trade.

4. Where is the Sewer Tunnel Key located?

The Sewer Tunnel Key can be found in the Control Room accessed through the Casterfell Woods region.

5. How do I access the Control Room in the Sewer Tunnels?

Follow the Maintenance signs to reach the locked Maintenance room outside the Control Room. The key needed for entry is located nearby.