Lake Pend Oreille | Pend Oreille River

Monitoring Our Wastewater

Similar to stormwater, ineffectively treated wastewater can be a dangerous source of pollution.

This is due to the presence of potential human pathogens, as well as high levels of nitrogen and phosphorous which can promote the growth of algae and aquatic vegetation.

Our team monitors National Pollutant Discharge Elimination System (NPDES) permits of wastewater treatment facilities that discharge effluent into our local waterways in order to ensure compliance.

We also review permit applications from treatment facilities that seek to discharge wastewater to our local waterways to ensure that proposed effluent limits are adequately protective of water quality.

Wastewater Treatment in Sandpoint

Currently, the City of Sandpoint is planning to update the wastewater treatment facility located at Lakeview Park that drains into the Pend Oreille River. In 2017, NPDES issued a new discharge permit to the City of Sandpoint which requires the city to either significantly upgrade the existing plant with five years or build a new treatment plan within ten years.

Since Sandpoint sits on soil that drains poorly, the ground water level rises quickly in response to any large amount of precipitation and leads to a large about of extra flow entering the City’s wastewater treatment plant. This requires Sandpoint to build a wastewater treatment plant that is twice the size of what is needed during regular flow periods and will require major costs to construct.

At the Sandpoint City Council meeting in August 2018, the Council voted to improve the existing site and add new technology to meet the new standards imposed by NPDES. The construction of the new plant is expected to be completed by 2024.

This new plant will be expensive, but in the long term will be better for the health of our lake. A new wastewater treatment system should reduce nitrogen and phosphorous loading and thereby reduce the risk of algal blooms in the lake.


Did you know?

The Environmental Protection Agency (EPA) has used data produced from our Water Quality Monitoring Program to help establish effluent limits for the City of Sandpoint’s wastewater discharge permit as well as the discharge permit for the Kootenai Ponderay Sewer District.

​Just one example of how our water quality data is being used by regulatory agencies.


Percent of wastewater treatment facilities across Idaho that failed to meet the requirements in their permit needed to protect water quality

According to a study done by Idaho Conservation League in 2020. Sandpoint’s treatment facility alone reported 16 violations of its wastewater discharge permit between 2017 to 2019, including high levels of bacteria, chemicals, and other contaminants. 

Wastewater Treatment Facilities Map


EPA – Nutrient Pollution – Wastewater
How wastewater from wastewater treatment plants and septic systems can contribute to nutrient pollution in our waterways.

NPDES – Permit for City of Sandpoint Wastewater Treatment Plant
The NPDES final permit and supporting documents for the the Wastewater Treatment Plant in Sandpoint.

City of Sandpoint – Wastewater Treatment Plant Facility Plan
The plan for Sandpoint’s new wastewater treatment facility prepared in 2018.

DEQ – Issued Permits and Water Quality Certifications
Searchable database for water quality certifications and permits issued by the Idaho Department of Environmental Quality.

DEQ – Water Quality – Wastewater
Information regarding wastewater in Idaho, such as treatment and collections, permit options, sludge and biosolids, pretreatment, storm water, and septic/septage.

Support this Program!

Our efforts to track wastewater pollution are supported by generous community funding and volunteer citizen scientists.

Become a Citizen Scientist!

Become a trained citizen scientist. Collecting water samples is a great way to enjoy time on the water & get involved in active stewardship of our local waterways!