The Washington State Department of Ecology (Ecology) has listed the Spokane River as having impaired water quality. Ecology has prepared a water quality cleanup plan (called a Total Maximum Daily Load or TMDL) to address the Spokane River's dissolved oxygen problem. Issued in draft in late 2004, the TMDL would require very significant reductions in phosphorous loading to the river over the next 10 years, a reduction current discussions among the parties aim to achieve by balancing important environmental goals and requirements with technical feasibility and a healthy economy.

Phosphorous is not a toxic contaminant; rather, it is a fertilizer that causes plant life to flourish, which is great for gardens, but not good for an aquatic environment. The natural life cycle of an aquatic plant demands oxygen from water, and when too much plant life exists, the microorganisms that eat the dead plant matter deplete the oxygen and other aquatic life suffers.

The current phosphorous standard in the Spokane River, established in 1989, is 569.8 pounds per day. Six “point-source” dischargers, or in this case municipal and industrial wastewater treatment plants along the river, may contribute no more than 336 pounds of phosphorous per day into the river. The remaining 233 pounds of phosphorous per day that reaches the river is from “non-point sources,” such as lawn fertilizers, agriculture, septic tanks and natural causes.

The new phosphorous standard proposed by Ecology would reduce the total amount allowed from 569.8 pounds to 251.4 pounds per day in two phases.

In the first phase, treatment plants would need to upgrade facilities with new technologies to collectively reduce the amount of their phosphorus discharge from the allowable 337.8 pounds to a collective total of 19.7 pounds per day, a reduction of 318 pounds per day. The cost to the region's ratepayers to make this improvement is estimated to be about $250 million, or roughly $788,000 per pound of phosphorous eliminated.

In phase two, the treatment plants would have to reduce phosphorous from 19.7 pounds per day to a collective 4.6 pounds of phosphorous per day, or a reduction of 15.1 pounds. Wastewater engineers and other experts estimate the cost to reduce this additional 15.1 pounds of phosphorous to be about $400 million over and above the phase one costs. That calculates to about $26.6 million per pound of phosphorous removed, or 30 times more expensive than the phase one cost per pound.

The two-phased proposed phosphorous standard by Ecology does not address the 233 pounds of non-point source phosphorous that reaches the river daily.