About the Washington Park Reservoir

Washington Park was previously home to two open-air reservoirs: the upper Reservoir 3 and the lower Reservoir 4. The reservoirs were part of an ingenious gravity‐fed drinking water system built in the 1890s. The original reservoirs served Portland for more than a hundred years.

In 2016, the Portland Water Bureau began a project to replace the original reservoirs with a 12.4-million-gallon underground reservoir. The modern reservoir has been serving water to more than 360,000 people since 2021, including all downtown businesses and residents, 20 schools, 5 hospital complexes, and more than 60 parks. 

View full size image of Landslide over the nearly completed Reservoir 4, taken in 1894.

Aging infrastructure: The two original reservoirs were over 100 years old and had serious structural issues. They were unstable and at risk of collapse during an earthquake.

Landslides: An ancient landslide under the site was slowly weakening the reservoirs’ structural integrity.

Public health regulations: Federal rules now require reservoirs to be covered to protect drinking water.

You may not know it, but the community helped shape what you see today! The Water Bureau knew this project was an opportunity to create new public access at the reservoir site. It was important for the community to help shape their future park space. 

View full size image of A group of people on a community tour, looking at construction progress of the reservoir.

From 2013 to 2014, the Portland Water Bureau, the design consultant team, and JLA Public Involvement led a three-part public process to center community input in the design of the new public space. A committee was created to represent a variety of perspectives. Committee members included:

• Portland Water Bureau and Portland Parks & Recreation staff, to help share information and expertise
• Participants from surrounding neighborhoods with diverse interests
• Historic preservation advocates

The thoughtful process helped the public not only understand the need for change but also imagine the future site. 

View full size image of Close up view of historic, wrought iron fencing with many decorative elements

The public's input shaped the design of the Washington Park Reservoir today: 

• The stepped, low profile of the reservoir preserves landscape views.
• The sound of the cascading water feature provides a sensory connection to the water.
• Historic fencing and other elements were preserved and restored.
• The lower reservoir area creates sustainable habitats for native plants and wildlife. The hill over the landslide is a wildflower meadow.
• Interpretive signs tell the story of this special site.

The original Washington Park Reservoirs were built on an ancient landslide that extends from the International Rose Test Garden down the hill to the reservoir area. In 1894, three weeks before the new water system opened, the landslide cracked one of the reservoir basins. It continued to damage both reservoirs until the City stabilized the soil in 2020.

We’re always working to build water infrastructure that can withstand landslides and earthquakes. The new reservoir keeps the historic look and feel of the original reservoir while using modern technology and building standards to make it seismically resilient.

We used innovative construction methods to address landslide and earthquake risks, including:

• Heavy, four-foot-thick concrete floors and walls, and 7.4 million pounds of rebar for seismic reinforcement
• 176 pilings embedded in stable bedrock to support the bottom of the reservoir
• State-of-the-art compressible material that absorbs shock from earthquakes and landslide movement

Hear a neighbor’s perspective on the project from Kathy Goeddel and Brooks Haxton.

In February 2022, the Water Bureau replaced some sensors that measure ground movement between the Portland Japanese Gardens and the Washington Park Reservoir. 

We will continue to replace sensors as part of ongoing maintenance. This ensures that we can gather accurate information about soil movement near the reservoir as part of our seismic planning efforts. Ground movement has slowed considerably since the reservoir improvements were made.

The Washington Park Reservoir is part of the Portland Water Bureau's plan for seismic resilience. Our goals were to protect the water supply and to make drinking water storage at Washington Park more reliable. Achieving these goals required an underground reservoir that was structurally and seismically sound.

No, the upper and lower reflecting pools are not part of Portland's drinking water system. Drinking water is in a covered reservoir underneath the upper reflecting pool.

View full size image of A cartoon map showing Portland's water system that starts near Mt Hood on the right and goes through Portland to Washington Park on the left. The map shows a lake and two dams and reservoirs in the Bull Run Watershed, the two water treatment facilities, the Columbia South Shore Well Field, and underground pipes and reservoirs that carry and hold our drinking water around town.

There is no swimming, boating, wading, or entering the water allowed in the Washington Park Reservoir reflecting pools. The reflecting pools are also off limits to pets.

The reflecting pool water is treated with low levels of chlorine to keep the reflecting pool free of algae. The reflecting pools are not chlorinated to the level required for a swimming pool or splash pad.

To report vandalism or trespass, call the Water Bureau's 24-hour security line at 503-823-6084.

Public swimming pools operated by Portland Parks & Recreation

The Washington Park Reservoir improvement project has spent $216 million to date. This project is part of the Portland Water Bureau’s seismic resilience plan and was paid for using ratepayer funds. Taxpayer funds were not used to pay for this project.

We invest in projects to ensure Portland’s sewer, stormwater, and water systems stay safe and reliable for generations to come.

How your ratepayer dollars support critical water system improvements

In June 2025, shortly before the community celebration at the site, Water Bureau leadership identified incomplete construction tasks and safety concerns that led to the difficult decision to keep the site closed to the public. 

Learn more about the project delays

The Washington Park Reservoir is operated by the Portland Water Bureau and is the site of critical water infrastructure. The primary goals of the reservoir improvement project were to protect the water supply and to provide reliable drinking water storage to the west side.

View full size image of Old black and white photo of two men standing on the stone Reservoir 3 dam

The structures and buildings on this site are considered historically significant. They are part of an early design for a municipal open water storage system, and they demonstrate early concrete engineering construction technology. The structures are also well-maintained examples of late-nineteenth-century architecture.

Because this space is a historic landmark, there are legal restrictions on how we can use it. For example, to maintain the site’s identity as a historic landmark, water must touch the dams of the old reservoirs. The community provided a lot of input on the site’s design in 2013 and 2014 and helped shape what you see today.

The reflecting pools are not chlorinated or filtered to the level required for a swimming pool. Please do not swim in, drink from, or allow pets inside the reflecting pool.

Public swimming pools operated by Portland Parks & Recreation

View full size image of A bird perched on the historic fencing at the lowland habitat.

Yes. In addition to building walkways and a reflecting pool above the new reservoir, we wanted to create a vibrant space at the former Reservoir 4 site. As part of that work, we developed a lowland habitat for all creatures to enjoy. There is now a reflecting pool and bioswale in the footprint of the former lower Reservoir 4.

View full size image of Man standing inside of Reservoir 4 with a tape measure showing damage of the concrete due to the slow moving landslide. Taken in 1975.

The original Washington Park reservoirs were unstable due to significant structural damage. A new reservoir was necessary to ensure safe and reliable water for Portland’s west side. The National Primary Drinking Water Regulations (40 CFR Part 141) state that drinking water reservoirs built after March 15, 2002, must be covered. 

View full size image of Inside of an underground reservoir while it is empty. It is a large, dimly lit room filled with supporting columns

The 12.4-million-gallon underground reservoir is under the space where upper Reservoir 3 used to be. A new reflecting pool on top of the underground reservoir was completed in 2025. Lower Reservoir 4 was decommissioned during the reservoir improvement project and replaced with a reflecting pool, low-land habitat and bioswale.

The historic light fixtures at Washington Park Reservoir date to 1905, when the original reservoirs were first filled. We worked to restore working fixtures and replace damaged fixtures. 

These stunning ironwork fixtures originally operated on gas systems. Each light fixture had to be lit by hand each night, then snuffed out each morning!

A local artisan shop worked to restore the original fixtures and bring them up to modern electrical standards. This was a long and very detailed process. Artisans removed corroded elements and hand-forged new details to match the original ironwork. We replaced missing fixtures with new fixtures cast from a mold of an original fixture. 

These stunning ironwork fixtures originally operated on gas systems. Each light fixture had to be lit by hand each night, then snuffed out each morning!

The historic lights at Washington Park Reservoir are identical to the original fixtures at the Mount Tabor reservoirs. We restored the light fixtures around Mount Tabor Reservoir 5 in 2024.

The reservoir's public space is closed at night. Gates will be shut and locked. Open hours are based on seasonal daylight hours: 

• Summer hours: Open from 8 a.m. to 8 p.m.
• Winter hours: Open from 8 a.m. to 4 p.m. 
• Fall and spring hours: Open from 8 a.m. to 6 p.m. 

The reservoir area will close occasionally for operations and maintenance work.

View full size image of Washington Park Reservoir reflecting pool and promenade.

The Washington Park Reservoir site has three entry areas:

• SW Sherwood Boulevard (wheelchair-accessible entrance)
• SW Sacajawea Boulevard (grand staircase entrance)
• SW Madison Drive walking and biking trail (plaza entrance)

The Washington Park Reservoir is designed with public access in mind and includes:

• Three bike racks on-site
• Two drinking water fountains
• Concrete seating walls along the upper reservoir walking paths
• Educational elements throughout the upper and lower spaces
• Wheelchair-accessible parking on SW Sherwood Boulevard
• Paid street parking along SW Sacajawea Boulevard

Public bathroom access is across the street on SW Washington Way, near the intersection of SW Park Place and SW Washington Way. 

You can help ensure everyone has a safe and rewarding experience while visiting by following all park rules. 

• No swimming
• Keep pets on leashes
• Stay on marked paths
• Don’t litter
• Respect the habitat areas
• No skateboarding
• No drones

View full size image of Washington Park Reservoir 2

Washington Park Reservoir has walking paths around the upper and lower reflecting pools. The upper reflecting pool promenade is flat and easily accessible for mobility devices and strollers. A wheelchair-accessible entrance is on SW Sherwood Boulevard near accessible parking spaces.

The walkway down to the lower reflecting pool is steep, and there is no exit from the lower area. Visitors must walk long distances to return uphill. This may be a challenge for people with mobility issues, strollers, or young children. We have closed the lower area for public use while crews work to develop signage and address other safety issues.

The Washington Park Free Shuttle runs a loop inside the park throughout the day. Shuttles usually arrive every 15 minutes. The nearest stops to the Washington Park Reservoir are at the Oregon Holocaust Memorial (wheelchair accessible) and the Park Place Entrance.

TriMet Bus Line 63 provides direct service between Pioneer Courthouse Square and the Washington Park Reservoir. The MAX light rail Red and Blue Lines both stop at the Washington Park station and link to the Washington Park Free Shuttle. Make your transit plans online using TriMet.

Paid street parking is available along SW Sherwood Boulevard and SW Sacajawea Boulevard near the Washington Park Reservoir. Pay to park using Parking Kitty or at pay stations.

Wheelchair accessible parking is available on SW Sherwood Boulevard near the entrance to the reservoir site.

There are three bike parking stations at the reservoir site. Bike parking is also located at all major attractions within the park.