Debunking Rumors

On this page, we will address rumors you may hear around town.  If you hear something that isn't on this page, feel free to call and ask us.  The Executive Assistant to the City Manager can be reached at 503.831.3502.

RUMOR:  Why are we building all these houses in the City when we don't have enough wastewater treatment plant capacity and enough drinking water?

FACTS:  The City has adequate capacity to support current and planned future development.

WWTP capacity: 
The City operates a Wastewater Treatment Plant (WWTP) that is built with designed treatment capacity inflow into the plant.

1. Monthly avg plant flow capacity for dry weather is 3.4mgd, we are avg 1.6 or 47% capacity
2. Monthly avg plant flow capacity for wet weather is 7.67mgd, we are avg 5.0 or 65% capacity
Total seasonal avg is 56% of capacity. 
These levels of capacity are sufficient

As these percentages get higher, steps being taken to minimize or reduce these totals include Inflow and Infiltration (I&I) projects that remove and replace sewer pipes that are worn and have ground water leaking into them. This conservation minded approach allows for added life span of the existing wastewater treatment plant. 

Water Source Capacity:
The City has sufficient water source at the Mercer Reservoir for the citizens of Dallas.
  • The reservoir has an estimated current capacity of 1,100  acre feet which is 358 million gallons
  • The Water Treatment Plant (WTP) capacity is 8.5 million gallons per day (MGD) and currently is producing 2 MGD to meet the needs of the City
  • The WTP has room for additional expansion
  • The highest demand for water during summer months has been 5 MGD 
Current practices in place or in the planning process to ensure adequate capacity or future needs include:
Low flow plumbing devices on new developments
Assessing options that may include dredging the Mercer reservoir to increase capacity or additional source water reservoirs.


RUMOR:  Is the City pumping raw sewage into Rickreall Creek?


FACTS:  Sewer overflows can occur when rainwater or groundwater enters the underground pipes that carry sewage to the treatment plant. The extra water can cause the pipes to overflow at the treatment plant, and result in the release of untreated sewage into the environment. Sewer overflows are quite common in the Willamette Valley, due to the winter rainfall. However, sewer overflows at the City of Dallas Wastewater Treatment Plant are rare and, when they occur, generally last only a fraction of a day. The City has been working to address sanitary sewer overflows by replacing older, leaking underground pipes, and removing direct connections where rainwater enters the sewer system. Over the last 3 years, the City has invested more than $1.5 million in projects to address rainwater or groundwater entering the system. System overflows during the last 5 calendar years are shown below:

 Year  Number  Description of Overflow(s)
 2013       0 No overflows 
 2014       1 March 8 for 5 minutes (equipment malfunction)
 2015       4 December 7 and December 18 due to a continuous storm*
 2016       1 November 24 & 25 for 24.5 hours
 2017       3 January 1 for 17 hours, February 5 for 15 hours, and February 9 for 14 hours

*The overflows in 2015 occured during the storm cycle which resulted in a federally declared disaster in the state of Oregon

This winter, the Willamette Valley has experienced extreme rainfall. As a result, sewer overflows are above our average of about 1 per year. The City has experienced 4 overflows over the last 4 months due to the abnormal precipitation. When overflows occur, the City follows our State and Federal permitting requirements and protocols. One of the requirements is to post signage downstream of the treatment plant. As a precaution, the signage always stays in place for several days - much longer than the duration of the overflow. For further questions, please contact the City at 503.831.3562.