{"uid":"cap_kTcrA38Z7hf0i787f884D","slug":"plumbing-pipe-flow-calc-pipe-size-selector-0dcc4ca4","name":"Plumbing & Pipe Flow Calc – Pipe Size Selector","description":"Smallest standard copper Type L or PVC Schedule 40 pipe that keeps water under a maximum velocity at your flow rate.","url":"https://plumbing-calc.x402tookit.com/pipe-size?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","required":["flowGpm"],"properties":{"flowGpm":{"type":"number","description":"Flow in US gallons per minute"},"material":{"type":"string","description":"copper-l or pvc-40 (default copper-l)"},"maxVelocityFps":{"type":"number","description":"Maximum velocity in feet per second (default 5; 8 is a common upper limit)"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","properties":{"asOf":{"type":["null","string"]},"source":{"type":["null","string"]},"flowGpm":{"type":["null","number"]},"reasons":{"type":["array","null"],"items":{"type":"string"}},"summary":{"type":["null","string"]},"verdict":{"type":["null","string"]},"allSizes":{"type":["array","null"],"items":{"type":"object","properties":{"nominal":{"type":["null","string"]},"velocityFps":{"type":["null","number"]},"insideDiameterInches":{"type":["null","number"]}}}},"degraded":{"type":["boolean","null"]},"material":{"type":["null","string"]},"disclaimer":{"type":["null","string"]},"notChecked":{"type":["array","null"],"items":{"type":"string"}},"maxVelocityFps":{"type":["null","number"]},"recommendedNominalSize":{"type":["null","string"]},"recommendedVelocityFps":{"type":["null","number"]}}}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.02","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.02/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_-baLrGQ5JMFJ0LVo_iLyb","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.02","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns the smallest standard copper Type L or PVC Schedule 40 pipe nominal size that keeps water velocity under a specified maximum for a given flow rate.","exampleAgentPrompt":"What's the smallest copper Type L pipe size I need for a 7.5 GPM flow rate, keeping the water velocity under 5 feet per second?","exampleUseCases":[{"title":"Residential water supply line sizing","prompt":"I'm roughing in a new bathroom and need to run a supply line — what's the smallest copper Type L pipe that can handle 4 GPM while keeping velocity under 5 fps?"},{"title":"Irrigation system PVC pipe selection","prompt":"I'm designing an irrigation zone that'll flow at 12 GPM — what's the minimum PVC Schedule 40 pipe size I should use, with a maximum velocity of 8 feet per second?"},{"title":"Avoiding water hammer in high-flow fixture","prompt":"I've got a commercial sink running at 15 GPM and I want to keep noise and water hammer down — what's the smallest copper pipe that stays under 4 fps velocity?"}],"resultDescription":"Returns the recommended nominal pipe size, the velocity at that size in fps, a summary explanation, a table of all standard sizes with their inside diameters and velocities, the input flow rate, material, maximum velocity threshold, and a disclaimer. Includes a degraded flag if data quality is reduced.","failureModes":["Missing required flowGpm parameter returns an error","Invalid material string (not 'copper-l' or 'pvc-40') may return an error or default to copper-l","Flow rates too low or extremely high may fall outside tabulated pipe sizes","Non-numeric flowGpm or maxVelocityFps values return validation errors","Network or service downtime returns HTTP error"],"whenToPreferThis":"Use this endpoint when you need a quick, standards-based pipe size recommendation for copper Type L or PVC Schedule 40 pipe given a known flow rate and velocity limit. It is ideal for residential, commercial, or irrigation plumbing design decisions where the goal is to select the smallest (most economical) pipe that meets velocity constraints. Prefer this over manual lookup tables or friction-loss calculators when velocity-based sizing is the primary concern.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-29T13:14:23.983Z","isFirstParty":false,"canonicalSlug":"plumbing-pipe-flow-calc-pipe-size-selector-0dcc4ca4"}