This was originally posted to: Guemes Island Planning Advisory Committee

Suggested Elements of a Rainwater Catchment System Program

Suggested Elements of a Rainwater Catchment System Program

The Guemes Island Planning Advisory Committee (GIPAC) is urging homeowners to consider using rainwater catchment in lieu of new wells for household water, both potable and non-potable. Toward that end, GIPAC is advocating changes to Skagit County code and practices to remove existing barriers to rainwater catchment, expedite county approvals, and make rainwater catchment systems as economically feasible as possible. This paper identifies program elements to achieve these goals.

Water Source Options in County Code

Skagit County code says that alternative systems for potable water (including rainwater collection) are discouraged, and will only be approved when the applicant shows why a public water system or drilled well cannot be used. (See Skagit County Code 12.48.250.) Historically, this meant that an applicant needed to drill a well first, that must came up dry or contaminated, before a rainwater catchment system could be considered.  

More recently, code language was added to the Critical Areas Ordinance that reverses the policy toward rainwater catchment systems: “Where a known seawater intrusion problem exists, alternative sources of water are encouraged, but must comply with the requirements of SCC 12.48.250.” (See SCC 14.24.380(3).)

The more recent code provision reflects the current thinking of county staff, but it still represents a conflict with the older code provision that says alternative systems are discouraged. 

GIPAC suggests: The code should be updated to resolve this conflict and remove any legal uncertainty about whether rainwater catchment systems are encouraged as an alternative to wells on Guemes Island. The code needs to be changed so that the new policy is formalized and doesn't rely on current staff and their code interpretations.  


System Designer

Skagit County requires a homeowner to use one of four designated engineering firms to design a rainwater collection system. GIPAC has been told this adds at least $5,000 to the price of the system for the engineer’s stamp; it also may add system costs for unnecessary materials and expensive design elements promoted by engineers.

This is in contrast to how homeowners on Guemes have often proceeded—using the “homegrown” expertise of island residents, contractors, and plumbers who know what works and what doesn’t. Nearby San Juan County allows rainwater systems to be designed by an engineer, an accredited water system designer, or by the homeowners themselves. Guidelines are provided, but the homeowner takes responsibility.

GIPAC suggests: Give homeowners maximum choice and make them legally responsible for their systems; or have the county provide a long list of approved plumbers, contractors, ARCSA (American Rainwater Catchment Systems Association) certified designers, and others with experience designing rainwater catchment systems.   


Level of Design Detail Specified by the County

Skagit County lacks a simple set of guidelines for homeowners (and contractors) to follow in designing rainwater catchment systems. For an example, see San Juan County's Guidelines

Note that there are other more detailed options. See, for example, ARCSA Guidelines prepared by a committee of engineers and the Technical Appendix on green plumbing recently adopted by Skagit County. (Note that there is a 2015 edition of the Green Plumbing and Mechanical Code Supplement and that the supplement is going to be moved within the building code sometime soon, so the web link to find this material may change.)  

GIPAC suggests: Stick with a simple set of guidelines. Those with experience tell us “it’s not rocket science”—there is no need to get overly elaborate with design requirements.


Definition of Adequate Water Supply

Skagit County code requires that a well produce 350 gallons per day (GPD) to meet the definition of “adequate water supply” but it’s not clear if this also applies to rainwater catchment systems. For rainwater systems, such a requirement would make the size and expense of a system infeasible for many small lots. In San Juan County, rainwater catchment systems are considered alternative sources; a covenant on the property title stating that the home is served by an alternative system is always required. The county provides a formula but the homeowner decides how much water (including storage) is needed or adequate.

GIPAC suggests: Many homeowners on Guemes report using 100 GPD or less per household. Numerous island homes are used only part-time, and most homeowners understand that water on the island is a limited resource that requires careful conservation. GIPAC suggests 50 GPD per person, which is the State Department of Ecology standard for rainwater catchment systems serving households that apply basic conservation measures such as low-flow toilets and water-efficient appliances. 



San Juan and Jefferson Counties require the property owner to file a covenant documenting that an alternative (rainwater) system serves the property. Skagit County staff note that the covenant requirement, coupled with giving property owners the discretion to design their own systems, serves to remove liability from the county for the adequacy of rainwater catchment systems. Jefferson County proactively encourages rainwater systems; their covenant includes conservation measures such as restricting outdoor use.

GIPAC suggests: A covenant should be required in order to disclose the alternative system to future property purchasers and to put the responsibility on the homeowner for long-term maintenance and operation of the system. 

GIPAC has discussed a possible recommendation that a water status disclosure be required—as a covenant in the property records or at least in a real estate disclosure form—for any type of water system serving a property on Guemes, be it a well, public water system, or rainwater catchment system.


Maintenance and Operations

Skagit County does not have operations and maintenance regulations for wells.

Skagit County recently adopted the Uniform Plumbing Code technical appendix on green plumbing (cited above) that requires frequent water quality testing for rainwater systems; wells have no such testing required. Catchment systems seem to be held to a higher (and more expensive) standard than wells. 

San Juan County requires a covenant in the property record that includes a property-owner commitment to a simple maintenance and operations plan.  

GIPAC suggests: Simplify the standards for rainwater catchment system operations and maintenance; make sure property owners know how to operate their systems safely; and insure equal treatment for wells and rainwater catchment systems so that the requirements don’t create a disincentive or discouragement for building rainwater catchment systems.


Rainwater Catchment for Non-Potable Use

Rainwater catchment can be very useful for irrigation and other non-potable uses, and can be addressed with much smaller systems that are less expensive and considerably more feasible on small lots. Shifting such uses from existing wells to catchment systems could significantly reduce water withdrawals from Guemes Island’s sole source aquifer.

GIPAC suggests: Skagit County should partner with GIPAC to promote rainwater catchment for irrigation and other non-potable uses through public education and incentives. Publicize the fact that rainwater catchment for non-potable use is encouraged and allowed without county approval. Consider ways to discourage use of well water for outdoor irrigation on Guemes Island.


Overall conclusions

Keep program requirements simple; rainwater catchment is not rocket science.

Keep program requirements as low-cost as possible for the applicants and the county. Remove unnecessary barriers such as the engineering stamp requirement (or other expensive consultant), design requirements that represent “overkill,” and extensive monitoring requirements that go beyond what’s required for well water.

Put responsibility on homeowners’ shoulders.

Minimize county liability by being an advisor rather than a regulator/certifier.

Draw heavily from what other counties have done—no need to reinvent the wheel.