Futurewise to Appeal Snohomish County Rural ADU Expansion

May 3, 2022

In March 2022, Snohomish County adopted Ordinance No. 22-006, which amended the regulations that apply to detached accessory dwelling units (ADUs) on rural lands and agricultural, forest, and mineral resource lands of long-term commercial significance.

Futurewise decided to appeal this ordinance on the grounds that it would allow excessive development in rural areas, resource lands, and farmland, contributing to sprawl, increased greenhouse gas emissions from transportation, and overdrawing limited water resources.

Before we get into the nuts and bolts of the ordinance and our appeal, let’s answer a few FAQs first!

  • What’s a “detached accessory dwelling unit (ADU)”? An ADU is a unit on a property that could be considered a separate living space, and is typically a smaller space than the main dwelling. An internal ADU is located inside an existing house or building, like a basement apartment or garage apartment. An attached ADU are added on to an existing house or building, like a mother-in-law suite. A detached ADU is a completely separate building constructed on the same lot, like a backyard cottage.
  • This sounds familiar. But wait, I thought Futurewise liked ADUs? In urban areas served by transit or with good walking and biking infrastructure, ADUs can be a fantastic low-impact way to increase housing options in neighborhoods. They can promote intergenerational households and provide lower cost living spaces to renters. The key point here is “in areas served by transit, walking or biking infrastructure.” In rural areas, resource lands, or farmland though, allowing ADUs can contribute to rapidly increasing development in far-flung areas.
  • Ok, one more question. I think I understand what a rural area is. Help me understand what “agricultural, forest, and mineral resource lands of long-term commercial significance” means. As you might already know, counties across Washington adopt comprehensive plans that determine where and how people live, work and play. Improving comprehensive plans is Futurewise’s bread and butter! In county comprehensive plans, they define areas that have different uses, especially areas that grow or produce things. For example, agricultural lands are where we grow crops, forest lands are our working forests that we periodically harvest for timber and mineral resource lands are places where we mine things. The goal with these designations is to protect these areas from development that threatens our local economy. The phrase “long-term commercial significance” refers to that connection to the local economy.

Ok, now that we’re all grounded in the same language, let’s dig into this ordinance and why Futurewise is appealing it.

What’s In the Ordinance?

Ordinance No. 22-006 made the following changes to the requirements for detached ADUs:

  • Detached ADUs are no longer prohibited on lots that do not meet the minimum lot sizes in the zone in which they are located. Detached ADUs are separate residences.
  • Detached ADUs are no longer prohibited on lots in the R-5 zone that are less than five acres in size. The minimum lot size in the R-5 zone is five acres.
  • Detached ADUs are no longer prohibited on lots in the RC zone that are less than 100,000 square feet in size.
  • Detached ADUs no longer have to be within 100 feet of the nearest walls of the primary dwelling. This was formerly required with certain exceptions.

We can look back at the history of ADU regulations and permits in Snohomish County to see the impact these changes will have. Between January 1, 2012, and December 31, 2019, the County issued permits for 100 ADUs in the rural area, an average of 13 per year. Nearly all, 97, were detached ADUs. Between 1994 and 2019, when detached ADUs were allowed on all lots in the rural area regardless of lot size, the County issued permits for an average of 28 ADUs a year.

The history of detached ADUs in Snohomish County indicates that the amendments adopted by Ordinance No. 22-006 will likely double the number of detached ADUs in the rural area at a time when the County is required to reduce growth in the rural area.

Why Futurewise Is Appealing

We have two major concerns about increasing detached ADUs in Snohomish County’s rural areas: water and greenhouse gas emissions.

We’re very concerned about increasing development in areas that already have limited water resources, especially areas primarily served by well water. Overdrawing wells can reduce stream flows that our local salmon runs rely on. The available data shows that detached ADUs use much more water than internal or attached ADUs because most water is used outside the home. The doubling of the number of detached ADUs allowed will increase water use. It will also increase impervious surfaces since the separate buildings will have a separate building footprint and will likely need an additional driveway especially as they no longer need to be close to the primarily dwelling. Since detached ADUs are now allowed on any size lot, the percentage of impervious surfaces will increase. Doubling the number of allowed detached dwelling units in the rural area and will harm water quality and fish and wildlife habitat because more trees and native vegetation will have to be removed to site an additional detached dwelling unit on the lot.

We’re also concerned about increasing development in areas that are not served by transit and which will contribute to longer commutes, more traffic, and increased greenhouse gas emissions. Last year, you successfully advocated with us to reduce the rural growth targets in Snohomish County. But this ordinance which would double the number of permitted detached ADUs will not reduce rural growth rates.

For these reasons, Futurewise is appealing Amended Ordinance No. 22-006 to protect fish and wildlife habitat, improve consistency with Puget Sound Regional Council’s VISION 2050, and to reduce greenhouse gas pollution.