South Deschutes County Groundwater Protection Project

Extensive field research and study has shown that the groundwater underlying south Deschutes County is threatened by continued use of traditional onsite wastewater treatment systems (standard, pressure distribution and sand filter systems). In addition, the La Pine National Demonstration Project showed that new types of onsite systems can protect the groundwater in a manner that meets the adopted Comprehensive Plan goals for Regional Problem Solving for South Deschutes County.

Beginning with a working group recommending a specific rule for south Deschutes County (Recommendation for Action and Consideration of a Geographic Rule, 1999) and continuing with the recommendation of an advisory committee (TDC Technical Advisory Committee) that met between July 2005 and April 2006, Deschutes County proposes to adopt a program to reduce the amount of pollution that are discharged from wastewater treatment systems, especially nitrogen. In addition, natural groundwater and surface water recharge patterns are maintained in this holistic approach to watershed-scale management of groundwater pollution loads in the La Pine Sub-basin.

Groundwater Protection Project Goals:

Recognizing that existing development and future growth can render groundwater resources in the La Pine sub-basin unusable, Deschutes County has focused on the following goals:

Prevent a moratorium on development;
Protect the primary, and currently high quality, source of drinking water for the residents in south Deschutes County;
Use extensive data and results to manage pollution so that financial and environmental impacts to residents in the La Pine sub-basin of the upper Deschutes River Watershed are minimized.

Local Rule for Groundwater Protection:

The Board of County Commissioners adopted Ordinance 2008-012 and Resolution 2008-021 on July 23, 2008. The new County Code was rescinded based on the outcome of a county-wide vote on March 10, 2009.

The new code would have required property owners to take groundwater protection actions to maintain and enhance the quality of the region's drinking water supply and rivers, including:

the use of advanced onsite systems, connection to sewer or other approach that protects groundwater quality
the use of groundwater protection measures on all properties by November 2022

Pharmaceuticals and Personal Care Products

Drugs in Drinking Water:

There has been a lot of coverage in the press lately about finding traces of prescription drugs and other personal care products in rivers across the nation and around the world. But did you know that the US Geological Survey performed a study right here in Deschutes County to study how these compounds and viruses move through soil and groundwater? The study first sampled septic tanks to find out what pharmaceuticals are found in septic tank discharges. Then the study looked at how well soils treat for drugs, bacteria and viruses. What the USGS found was that soil does a great job at removing pharmaceuticals, personal care products and microscopic organisms. The USGS completed a study in south Deschutes County in 2005 where one of the main findings was that samples taken right below septic system drainfields "demonstrated that organic wastewater compounds are mostly attenuated after unsaturated-zone transport of 1 foot." (Check the link to Pharmaceuticals and Coliphage in Ground Water.)

Existing Residences in High Groundwater Areas

In the past, Deschutes County denied proposals to replace or remodel previously existing residences in high groundwater areas (groundwater less than 24 inches from ground surface). Current information and experience shows:

Nitrates and Drinking Water: A Health Concern?

The US Environmental Protection Agency has established a standard for nitrate as nitrogen in drinking water under the Safe Drinking Water Act of 10 mg/L nitrate-nitrogen (also referred to as parts per million). This level was set in order to prevent cases of methemoglobinemia, a condition also known as blue baby syndrome, where an infant's blood cells carry nitrogen instead of oxygen. This condition may occur in infants under six months of age that are exposed to high levels of nitrate in drinking water because their gastroint

What's Required Now for Southern Deschutes County

Groundwater Protection Action:

Why Use Onsite Systems?

Ordinance 2008-109 adopted by the Board of County Commissioners requires the use of groundwater protection for new construction and major repairs and alterations. The information provided below identifies reasons why onsite wastewater treatment systems are a focus of county action.

Financial Assistance

The County has financial assistance monies available to provide financial assistance in the form of a partial rebate to property owners who have completed a retrofit of an existing onsite system serving a residence. This program is dependent on available funds and the County may cease this program at any time.

How well do onsite systems work?

Conventional onsite systems have been in use for decades and they do a very good job at what they were designed to do: reduce human contact with disease causing organisms. Conventional onsite systems include standard, pressure distribution and sand filter systems and they do a tremendous job at reducing bacteria as sewage is treated in the drainfield or sand filter. These systems also do a good job at reducing the quantity of solids (total suspended solids or TSS) and reducing a water quality measure called biochemical oxygen demand (BOD).

New or Expanded Sewer Systems

On January 4, 2008, the Oregon Department of Environmental Quality (DEQ) issued a letter that determined that a public health hazard* is being created in the region by continued use of conventional onsite wastewater treatment systems. The DEQ states that potential solutions to this public health hazard may include a variety of approaches ranging from onsite wastewater treatment systems to expanded or new sewer systems.

La Pine National Demonstration Project

Groundwater quality in the La Pine area of southern Deschutes County is at risk of nitrate contamination from onsite sewage treatment system discharge to groundwater. Nitrate concentrations detected in groundwater indicate that degradation of groundwater quality is in process in the densely developed areas. Most onsite systems in the region are conventional systems located in highly porous and permeable (rapidly draining) soils with no intervening layer protecting the underlying shallow aquifer.