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Cowlitz County, WA Outdoor Lighting: Light Trespass & Shielding (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

Applies to
commercial/light industrial use in AG-I zone
Standard
lighting directed, shielded or screened, § 18.10.502(H)
Related standard
stormwater sized for 25-year storm, subsection (B)
Enforcement tool
Director/Planning Commission may require monitoring instruments
Civil penalty
$1,000 per violation, § 2.06.080

Summary

In unincorporated Cowlitz County's Agriculture-Industrial (AG-I) zone, Cowlitz County Code § 18.10.502(H) requires that lighting on commercial or light industrial development be directed, shielded or screened so it is not cast, directly or indirectly, into adjacent or nearby residential areas or into the eyes of motorists on public or private roads.

These county ordinances apply to unincorporated areas of Cowlitz County. Incorporated cities within the county may have their own rules that take precedence over county-level regulations.

The following performance standards apply to any commercial or light industrial use in the AG-I zone, and are in addition to other applicable standards. ... H. Glare. ... Lighting shall be directed, shielded or screened so that it will not be directly or indirectly cast into adjacent or nearby residential areas, or hinder motorists on public or private roads.

Full Breakdown

580. Subsection H, titled 'Glare,' is the county's light-trespass rule: it requires that lighting, including permitted illuminated signs referenced in subsection A, be directed, shielded or screened so that it does not spill into adjacent or nearby residential areas or hinder motorists. 94 RCW and Southwest Air Pollution Control Authority rules (subsection E). Subsection I lets the county's Director or Planning Commission require the property owner to install monitoring instruments for glare and other nuisances if a complaint arises. 502 is written for the AG-I zone's commercial and light industrial development, lighting complaints between two houses in a residential district (RR-1, RR-2, RR-5, SR, UR) are not addressed by this glare standard; those disputes fall to general nuisance law rather than this zoning-specific lighting rule.

Violations & Fines

A commercial or light industrial development in the AG-I zone whose lighting is not shielded, directed or screened away from adjacent residential areas violates the § 18.10.502(H) glare standard, a Land Use Ordinance violation under Chapter 18.10 CCC. CCC § 2.06.040 makes the violation a civil infraction, and § 2.06.080 assesses a $1,000 penalty per violation, doubling for a second violation of the same ordinance within three years.

Frequently Asked Questions

Does Cowlitz County regulate light spilling onto a neighbor's property?
Within the AG-I zone, yes. CCC § 18.10.502(H) requires that lighting on commercial or light industrial development be directed, shielded or screened so it is not cast into adjacent or nearby residential areas or into the path of motorists.
Which properties does the county's glare standard apply to?
Section 18.10.502 applies to commercial or light industrial uses located in the Agriculture-Industrial (AG-I) zone district. It is layered on top of, not a substitute for, the general development standards at CCC §§ 18.10.500-18.10.580.
Can the county require a business to fix its outdoor lighting after a complaint?
Yes. CCC § 18.10.502(I) lets the Director or Planning Commission require the owner or operator of a development to install and operate instruments to monitor or control glare, along with noise, heat, air pollution or vibration.

Sources & Official References

Other rules in Cowlitz County

All Cowlitz County rules

Compare Cowlitz County to another location·View the Washington outdoor lighting overview

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