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The Montgomery County Reservoir is an abandoned water treatment plant in the Capital Wasteland in 2277. It is located northwest of the Reclining Groves Resort Homes and a home for up to a half dozen raiders and, depending on level, a sentry bot. There are ammunition boxes in the upstairs of the barn and in a silo to the northwest.


The treatment station serves as a stopping point in the mid-northwest part of the map. There is drinking water available with only 2 rads, acquired by using the wheel on two of the four circular water tanks.

There is also an abandoned barn to the northwest, where three ammunition boxes (one Very Easy locked) can be found on the second floor, as well as a "fake" pre-War book and a bottle of vodka (with Broken Steel). West of the barn is three more unlocked ammunition boxes in a makeshift shelter.

Inside the silo next to the barn, there is an assault rifle and a carton of cigarettes in the middle of the floor and a first aid box in the upper lefthand corner. There is a ladder leading up to the silo's walkway with two ammunition boxes (one Easy locked). Going into the silo may spawn a group of Talon Company mercs or Regulators, depending on Karma level.


  • The silo located at Montgomery County Reservoir is added in Broken Steel. Aside from decorative items such as potentially stolen barrels of Aqua Pura it contains munitions (ammunition boxes and an R91 assault rifle) and a first aid box.
  • The raiders respawn roughly every three game days.


Montgomery County Reservoir appears only in Fallout 3.

Behind the scenes

The Montgomery County Reservoir is based on the real world location of the Triadelphia Reservoir in Montgomery County, Maryland.


PCPC A short distance north of the site, there is a cliff that has not had the rocks along the bottom textured properly, and the player character will be able to walk behind them by going to the east side of the cliff and walking west into it. The player character will be able to see outside to the south but will not be able to walk through the rocks. They can escape by walking through the same area they entered through. [verified]