{"id":31,"date":"2025-09-23T04:50:54","date_gmt":"2025-09-23T09:50:54","guid":{"rendered":"https:\/\/plumbing101.i234.me\/wordpress\/?p=31"},"modified":"2025-09-23T04:50:54","modified_gmt":"2025-09-23T09:50:54","slug":"seattle-basement-bath-smart-upc-dwv-plan","status":"publish","type":"post","link":"https:\/\/plumbing101.i234.me\/wordpress\/seattle-basement-bath-smart-upc-dwv-plan\/","title":{"rendered":"Seattle Basement Bath: Smart UPC DWV Plan"},"content":{"rendered":"<article>\n<header>\n<h1>Seattle Basement Bath: Smart UPC DWV Plan<\/h1>\n<p><strong><a href=\"https:\/\/plumbing101.i234.me\" target=\"_blank\" rel=\"noopener\">(plumbing101.i234.me)<\/a><\/strong><\/p>\n<\/header>\n<section>\n<h2>Question<\/h2>\n<p>I\u2019m renovating a surprise basement bathroom in Seattle.<\/p>\n<p>All drains are under the slab and tie into the kitchen stack.<\/p>\n<p>I drew a plan, but I worry about the slope and the horizontal vent.<\/p>\n<p>Specifics:<\/p>\n<ul>\n<li>Where should the end-of-line cleanout go?<\/li>\n<li>Can I use a Fernco to join PVC to a galvanized vent?<\/li>\n<li>Is my horizontal wet vent legal under the UPC?<\/li>\n<li>All vents and fixture drains are 2\u2033; the main is 3\u2033.<\/li>\n<\/ul>\n<\/section>\n<section>\n<h2>Answer<\/h2>\n<p><strong>Use a 2\u2033 lavatory drain as the horizontal wet vent for the bathroom group, keep the lav\u2019s dry vent vertical until at least 6\u2033 above the flood rim before any horizontal, provide an accessible 3\u2033 end-of-line cleanout and a cleanout at the base of the vent, and use a shielded transition coupling (not an unshielded rubber sleeve) to join PVC to galvanized above ground.<\/strong><\/p>\n<\/section>\n<section>\n<h3>Cleanouts that pass inspection<\/h3>\n<ul>\n<li>Install a 3\u2033 cleanout at the upstream terminal of the 3\u2033 branch (often left of the toilet, in a wall or a floor box).<\/li>\n<li>Add a 2\u2033 cleanout at the base of the lav vent (accessible in the wall).<\/li>\n<li>Provide cleanouts at changes in direction exceeding 135\u00b0 and every long run as required.<\/li>\n<li>Maintain the required working clearance in front of each cleanout.<\/li>\n<\/ul>\n<\/section>\n<section>\n<h3>Wet venting under the UPC (Seattle)<\/h3>\n<ul>\n<li>Horizontal wet venting is allowed for one bathroom group on the same floor.<\/li>\n<li>Run the lavatory drain in 2\u2033. That pipe is the wet vent serving the toilet and tub\/shower.<\/li>\n<li>Use a 3\u2033 closet bend and wye into the 2\u2033 lav wet-vented line, then to the 3\u2033 main.<\/li>\n<li>Keep the lav\u2019s dry vent vertical to 6\u2033 above the highest flood rim before any horizontal run.<\/li>\n<li>Hold \u00bc\u2033 per foot slope on under-slab horizontals and avoid bellies.<\/li>\n<\/ul>\n<\/section>\n<section>\n<h3>Joining PVC to galvanized above-ground<\/h3>\n<p>Use a <em>shielded<\/em> transition coupling (often labeled \u201cProflex\u201d or \u201cshielded no-hub\u201d).<\/p>\n<p>Unshielded, all-rubber sleeves are typically for <em>underground<\/em> only and are not approved above ground.<\/p>\n<\/section>\n<section>\n<h3>Practical tips before you cut concrete<\/h3>\n<ul>\n<li>Verify the existing 3\u2033 tie-in elevation to confirm slope availability.<\/li>\n<li>Use long-sweep combos for under-slab joins; avoid hard 90s.<\/li>\n<li>Respect trap-arm limits and vent sizing per UPC and local amendments.<\/li>\n<li>Sketch pipe depths on the slab to plan trench width and clearances.<\/li>\n<\/ul>\n<\/section>\n<section>\n<h3>Helpful resources<\/h3>\n<ul>\n<li><a href=\"https:\/\/www.seattle.gov\/sdci\/codes\/codes-we-enforce-%28a-z%29\/plumbing-code\" target=\"_blank\" rel=\"noopener\">Seattle Plumbing Code (UPC with Seattle amendments)<\/a><\/li>\n<li><a href=\"https:\/\/epubs.iapmo.org\/2021\/UPC\/\" target=\"_blank\" rel=\"noopener\">2021 UPC \u2014 Wet Venting &amp; Cleanouts<\/a><\/li>\n<li><a href=\"https:\/\/forms.iapmo.org\/email_marketing\/codespotlight\/2017\/jun29.htm\" target=\"_blank\" rel=\"noopener\">IAPMO Code Spotlight: Cleanouts<\/a><\/li>\n<li><a href=\"https:\/\/forms.iapmo.org\/email_marketing\/codespotlight\/2021\/mar11.htm\" target=\"_blank\" rel=\"noopener\">IAPMO: Vents &amp; horizontal rules near flood rims<\/a><\/li>\n<li><a href=\"https:\/\/www.fernco.com\/plumbing\/shielded-couplings\/proflex-couplings\" target=\"_blank\" rel=\"noopener\">Shielded \u201cProflex\u201d transition couplings (PVC\u2194galvanized)<\/a><\/li>\n<\/ul>\n<\/section>\n<footer>I&#8217;m Chris Mayer, plumbing for <a href=\"https:\/\/plumbing101.i234.me\" target=\"_blank\" rel=\"noopener\"><strong>Plumbing 101<\/strong><\/a>.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-medium wp-image-15\" src=\"https:\/\/plumbing101.i234.me\/wordpress\/wp-content\/uploads\/2025\/09\/Seattle-Basement-Bath-Smart-UPC-DWV-Plan-1-300x242.png\" alt=\"\" width=\"300\" height=\"242\" srcset=\"https:\/\/plumbing101.i234.me\/wordpress\/wp-content\/uploads\/2025\/09\/Seattle-Basement-Bath-Smart-UPC-DWV-Plan-1-300x242.png 300w, https:\/\/plumbing101.i234.me\/wordpress\/wp-content\/uploads\/2025\/09\/Seattle-Basement-Bath-Smart-UPC-DWV-Plan-1-1024x827.png 1024w, https:\/\/plumbing101.i234.me\/wordpress\/wp-content\/uploads\/2025\/09\/Seattle-Basement-Bath-Smart-UPC-DWV-Plan-1-768x620.png 768w, https:\/\/plumbing101.i234.me\/wordpress\/wp-content\/uploads\/2025\/09\/Seattle-Basement-Bath-Smart-UPC-DWV-Plan-1.png 1128w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/p>\n<\/footer>\n<\/article>\n","protected":false},"excerpt":{"rendered":"<p>Seattle Basement Bath: Smart UPC DWV Plan (plumbing101.i234.me) Question I\u2019m renovating a surprise basement bathroom in Seattle. All drains are under the slab and tie into the kitchen stack. I drew a plan, but I worry about the slope and the horizontal vent. Specifics: Where should the end-of-line cleanout go? Can I use a Fernco&hellip; <a class=\"more-link\" href=\"https:\/\/plumbing101.i234.me\/wordpress\/seattle-basement-bath-smart-upc-dwv-plan\/\">Continue reading <span class=\"screen-reader-text\">Seattle Basement Bath: Smart UPC DWV Plan<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":15,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_wpscp_schedule_draft_date":"","_wpscp_schedule_republish_date":"","_wpscppro_advance_schedule":false,"_wpscppro_advance_schedule_date":"","_wpscppro_dont_share_socialmedia":null,"_wpscppro_custom_social_share_image":0,"_facebook_share_type":"default","_twitter_share_type":"default","_linkedin_share_type":"default","_pinterest_share_type":"default","_linkedin_share_type_page":"","_instagram_share_type":"default","_medium_share_type":"default","_threads_share_type":"default","_google_business_share_type":"default","_selected_social_profile":[],"_wpsp_enable_custom_social_template":false,"_wpsp_social_scheduling":{"enabled":false,"datetime":null,"platforms":[],"status":"template_only","dateOption":"today","timeOption":"now","customDays":"","customHours":"","customDate":"","customTime":"","schedulingType":"absolute"},"_wpsp_active_default_template":true},"categories":[79],"tags":[24,69,67,68,65,66,23,64],"class_list":["post-31","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-general-plumbing-help","tag-basement","tag-bath","tag-dwv","tag-plan","tag-seattle","tag-smart","tag-uncategorized","tag-upc","entry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/plumbing101.i234.me\/wordpress\/wp-json\/wp\/v2\/posts\/31","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/plumbing101.i234.me\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/plumbing101.i234.me\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/plumbing101.i234.me\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/plumbing101.i234.me\/wordpress\/wp-json\/wp\/v2\/comments?post=31"}],"version-history":[{"count":1,"href":"https:\/\/plumbing101.i234.me\/wordpress\/wp-json\/wp\/v2\/posts\/31\/revisions"}],"predecessor-version":[{"id":32,"href":"https:\/\/plumbing101.i234.me\/wordpress\/wp-json\/wp\/v2\/posts\/31\/revisions\/32"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/plumbing101.i234.me\/wordpress\/wp-json\/wp\/v2\/media\/15"}],"wp:attachment":[{"href":"https:\/\/plumbing101.i234.me\/wordpress\/wp-json\/wp\/v2\/media?parent=31"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/plumbing101.i234.me\/wordpress\/wp-json\/wp\/v2\/categories?post=31"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/plumbing101.i234.me\/wordpress\/wp-json\/wp\/v2\/tags?post=31"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}