Cascade Groundwater Alliance

CGA funded several projects to prepare to deliver safe, reliable groundwater from testing to treatment to tap. 

Groundwater wells

Nine wells will pump groundwater from Sand and Gravel Aquifer – over 600 feet below ground. To add water capacity, five new wells were drilled:

• Cascade Well 6: 223^rd Avenue
• Cascade Well 7: 202^nd and Glisan
• Cascade Well 8: 141^st Avenue
• Cascade Well 9: Kirk Park
• Cascade Well 10: North Gresham Elementary.

Water treatment

Three state-of-the-art treatment plants will ensure our water meets or exceeds state and federal water quality standards.

Gresham’s commitment to water quality was recognized in 2025. Gresham was awarded the designation as an Outstanding Performer by the Oregon Health Authority. The award recognizes excellence in treating, storing and delivering drinking water. We are committed to providing safe, high-quality water to the community.

Water Pipeline

10 miles of larger diameter water pipe will carry water from wells to treatment plants to storage and delivery.  

Water storage

Three modern storage tanks will ensure there is enough water year-round and for emergencies

Background

The City purchases water from the City of Portland. Portland runs and operates the Bull Run surface water system. Federal rules now require Portland to treat Bull Run surface water to protect it from microbial pathogens.

Cost savings

A new Bull Run Water filtration system is expected to cost over $2 billion. Scheduled rate increases to cover the cost of the new Bull Run treatment facility would impact all customers. City residents will benefit from smaller rate increases thanks to a transition to groundwater. 

Safe and reliable

• Groundwater is clean, reliable and consistent. 
• Groundwater is less impacted by earthquakes, fires and extreme weather, making it a safer water source in emergencies. 
• Gresham residents already drink groundwater from the Cascade Well Field. CGA projects expanded the capacity by drilling more wells and water treatment facilities.

About groundwater

1. Groundwater is fresh water (from rain/snow) that soaks into soil and is stored in and moves slowly through soil, sand and rocks – called aquifers.  
2. Gresham’s groundwater comes from the Sand and Gravel Aquifer, located approximately 600-1200 feet below the surface. 
3. The Sand and Gravel Aquifer is a large, sustainable and confined aquifer. 
4. A well – a pipe in the ground – is drilled into the aquifer. This fills with groundwater and is brought to the surface by a pump, and after treatment, is ready to drink.

Hydrogeologists confirm there is enough replenishable water in the Sand and Gravel Aquifer to supply Gresham residents.

• Our treatment facility will be upgraded to ensure water quality standards.
• The City will expand our groundwater protection program to limit surface contamination. Water is pumped 600-1200 feet below ground making contamination from the surface less likely. 
• Gresham conducted a pilot program and study in 2018 to test for and treat manganese, a natural mineral element. The planned treatment facility will filter manganese using sand filters.
• In 2020, Gresham conducted a pilot study to determine the best water treatment methods that would exceed federal requirements.

Resources 

• Environmental Protection Agency water quality standards
• State of Oregon drinking water protection

Documents 

• Rockwood PUD, groundwater development master plan, executive summary

Water quality

The City manages water quality programs to protect and monitor drinking water. 

• Groundwater protection program
• Water quality

The Cascade Groundwater Alliance will share the cost to expand our water supply system. Gresham will invest 70 million dollars over the next five years. 

Federal loan

Gresham received a $34 million Water Infrastructure Finance and Innovation Act (WIFIA) loan, which provides ratepayers savings from traditional debt because of low rates and flexible structure (it functions like a line of credit in that we only pay interest on what we draw; to date, delaying draws has saved our ratepayers more than $1 million in interest payments).   

• Environmental Protection Agency press release
• WIFIA project loan fact sheet

Gresham also received $4.5 million in a forgivable loan to support the treatment facilities at the Rockwood Water People's Utility District site.

Utility rate package

Council approved a five-year water utility rate package that went into effect Jan. 1, 2023. The rate increase covers water, stormwater and wastewater service. The water rate increase will help fund the expansion of our groundwater system. 

• Rates typically increase every year; Council adopts a five-year rate package to provide cost certainty to businesses and residents.
• This increase is significantly less than if the City had continued to purchase water from Portland.
• We are committed to offering customers who qualify assistance with their water bills. The City will expand utility assistance and other tools to help customers with billing needs.

 Learn more about Gresham utility rates.