ADU Utility or Impact Fee Charges

[brad.mcilrath]

Hello Everyone,

Our City Council is having a discussion in a few weeks about detached ADUs. Currently the city only allows internal or attached ADUs. A recurring concern from the Mayor and City Council is the impact on the infrastructure, specifically sewer impact. Do your cities charge an additional utility fee or impact fee to help cover the potential increased impact on the city infrastructure?

[jcboal]

It is important to understand and clarify what standards your public utilities are using for “capacity” and “demand”. The existing lines may have capacity for additional units, but the engineers may like to have additional breathing room. How is your demand being calculated (i.e. dwelling square footage, number of fixtures, etc.) and does that match the dwellings being built and/or the demographics of your community. It is important to have a data backed conversation on what the existing capacity is, what current demand is and what future demand will be created with the additional ADU’s.

For example, the sewer lines may be designed to have capacity for 8,000 square foot homes with 4 bathrooms and an occupancy of 8 people, but the current demand is actually 3,500 sq ft homes with 3 bathrooms and an occupancy of 4 people. Adding a 800 sq ft ADU with one bathroom would not exceed the capacity limit.

[Nicole Masson]

This really is a local policy decision – are you trying to encourage this affordable housing alternative or not or something in between.  I think there is no right answer – just have to figure how important having a detached ADU is to addressing the housing crisis. I’ve seen quite a few waive park fees.  The occasional additional unit (and they are occasional – ADUs are not going to show up on every lot (a fear I hear a lot)), likely does not impact your infrastructure in a significant way. 

 John Janson

[Author]

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