The problem with answering your question is land use/zoning laws and codes vary by municipality and even by neighborhood when restrictive covenants are in play. It would be worth looking into whether the properties in your neighborhood have such restrictions. Beaverton does require a building permit when erecting any fence higher than 6'. What this likely means for you is you may be able to build it higher than 6', but it is going to require some pre-approval. I've included a link you may find helpful in navigating the building permit process in Beaverton. Hope that gets you moving in the right direction!
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