How to Stop a Running Toilet (Flapper Replacement) in Portland, OR
Toilets in Portland's pre-1970s Craftsman and Bungalow homes often run on original or early-replacement fill valves that weren't designed for the region's very soft Bull Run water, and worn seals here commonly cause a constant hiss or a slow leak into the bowl. This guide walks through the exact flapper fix that solves the vast majority of running-toilet calls in older Portland homes.
📺 Video Tutorial: https://youtu.be/KXzYIhhfOuA
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📋 Step-by-Step Manual
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Step 1: Turn off the water supply
Turn the shutoff valve behind the toilet clockwise until it stops, cutting off water to the tank.
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Step 2: Drain the tank
Flush the toilet and hold the handle down to let as much water as possible drain from the tank.
💡 Tip: Sponge out the last inch of water so you're not reaching into a full tank. -
Step 3: Detach the old flapper
Unclip the flapper's ears from the pegs on either side of the overflow tube, then disconnect the chain from the flush lever.
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Step 4: Match and buy the right flapper
Bring the old flapper with you (or match the brand/model) — flapper size and shape vary between toilet brands like Kohler, American Standard, and Toto.
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Step 5: Install the new flapper
Clip the new flapper onto the same pegs, then attach the chain to the flush lever with a little slack — about 1/2 inch when the flapper is closed.
💡 Tip: Too much chain slack causes double-flushing; too little keeps the flapper from sealing, which causes the running-water sound. -
Step 6: Turn the water back on and test
Open the shutoff valve, let the tank refill, and flush a few times to confirm the toilet shuts off completely and doesn't keep hissing.
📍 Portland Tips for This Repair
- Portland's water is soft, so mineral scale on the flapper seat is less common here. A running toilet is more likely a worn or warped flapper, a misadjusted chain, or a tired fill valve.
- Replacing a flapper or fill valve is repair of an existing toilet's parts. Installing a brand-new toilet is fixture replacement, which Portland's permit rules may cover. Confirm with BDS before swapping the whole toilet.
- In older Portland homes, the shut-off valve under the tank can be stiff from age. Do not force it. Use the home's main shut-off if it will not close.
❓ Portland Repair FAQ
Do I need a permit to replace a toilet in Portland?
Portland's permit rules cover installing or replacing plumbing fixtures such as toilets, while repairing existing fixtures and their parts is treated differently. Replacing only a flapper or fill valve is a repair. For a full toilet replacement, confirm with the Bureau of Development Services.
Why does my toilet keep running even though Portland water is soft?
Soft water means less mineral scale, so the usual suspects are a worn or warped flapper, a misaligned chain, or a worn fill valve. The steps in this guide cover the flapper replacement.
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More Portland Repair Guides
Portland Housing Context
Much of Portland's housing stock is 1920s-1970s Craftsman and Bungalow-style homes, many still running on original galvanized steel supply piping and early-generation electrical panels. Decades of internal corrosion in that piping is a leading cause of low water pressure and pinhole leaks, and the region's damp, poorly-vented crawlspaces are a common source of moisture and mold around plumbing fixtures.
Portland Water Quality
Portland draws its water from the Bull Run watershed, one of the softest municipal water supplies in the country. Soft water is gentle on skin and appliances, and it is naturally somewhat corrosive to metal piping. The Portland Water Bureau adds treatment to raise pH and reduce that effect, but decades of exposure can still contribute to internal wear in older galvanized and copper plumbing found in the city's pre-1970s homes.
Municipal Permit & Code Guidance
Some plumbing and electrical work in Portland may require a permit or inspection under local building code, especially anything involving new supply lines, panel upgrades, or moving fixtures. The steps below cover minor, homeowner-performed maintenance only — for any work that may require a permit, contact the Portland Bureau of Development Services (BDS) before starting.
For this repair in Portland: Replacing a flapper or fill valve is repair of an existing toilet's parts. Installing a brand-new toilet is fixture replacement, which Portland may require a plumbing permit for. If you plan to swap the whole toilet, confirm with the Bureau first.
Portland lets homeowners do their own plumbing work on the home they live in, but the homeowner must be the recorded property owner (not an LLC).
Permit notes last reviewed October 2026 against official city and state pages. Rules change, so confirm before you start.
Visit Portland Bureau of Development Services (BDS) →FixOrPro AI is not a substitute for local code review. Always verify permit requirements with your local building department before performing electrical, plumbing, or structural work.