# Plumbing & Pipe Flow Calc – Drain Slope Calculator

> Plumbing & Pipe Flow Calc – Drain Slope Calculator is a paid API for AI agents from plumbing-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Calculates the fall needed for a drain run at a given slope in inches per foot, or derives the slope from a measured fall, and compares against typical plumbing code minimums.

## Facts

- Endpoint: GET https://plumbing-calc.x402tookit.com/drain-slope?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/plumbing-pipe-flow-calc-drain-slope-calculator-f3f15f8c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_PVROTO9vifuGXfixuBCq0

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability plumbing-pipe-flow-calc-drain-slope-calculator-f3f15f8c
```

Example prompt: I have a 20-foot horizontal drain run for a 4-inch pipe — can you calculate how many inches of fall I need at the standard 1/4-inch-per-foot slope and tell me if it meets code minimums?

## When to prefer this

Choose this endpoint when you need to quickly calculate or verify drain pipe slope and fall for plumbing rough-in or inspection purposes, especially when you want a comparison against typical code minimums. It is ideal for contractors, homeowners, and building inspectors working with horizontal drain runs. Prefer this over a general-purpose calculator when you need plumbing-specific outputs like inches-per-foot slope, code compliance flags, and multi-unit slope representations in a single call.

## Known failure modes

- Missing required runFeet parameter returns an error
- Non-numeric or negative runFeet value causes a validation error
- Providing neither fallInches nor inchesPerFoot results in default slope (0.25 in/ft) being used
- Unknown or unsupported pipe diameter may result in notChecked fields being populated
- Service may return degraded:true if reference data is partially unavailable

## How this service works

Fall needed for a drain run at a given slope in inches per foot, or the slope of a measured fall, with typical code minimums.

## Output

Returns the computed fall in inches and centimeters, the slope expressed in inches per foot, percent, degrees, and ratio form, a boolean indicating whether the slope meets typical code minimums, the typical minimum slope for reference, a human-readable summary and verdict, plus any disclaimers or notes about what was not checked.

## Request schema (JSON Schema)

```json
{
 "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": [
      "runFeet"
     ],
     "properties": {
      "runFeet": {
       "type": "number",
       "description": "Horizontal run in feet"
      },
      "fallInches": {
       "type": "number",
       "description": "A measured fall in inches, to get the slope instead"
      },
      "inchesPerFoot": {
       "type": "number",
       "description": "Slope in inches of fall per foot (for example 0.25); default 0.25"
      },
      "pipeDiameterInches": {
       "type": "number",
       "description": "Drain diameter in inches, to compare with the usual minimum slope"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "fallCm": {
       "type": [
        "null",
        "number"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "runFeet": {
       "type": [
        "null",
        "number"
       ]
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "fallInches": {
       "type": [
        "null",
        "number"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "slopeDegrees": {
       "type": [
        "null",
        "number"
       ]
      },
      "slopePercent": {
       "type": [
        "null",
        "number"
   
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/plumbing-pipe-flow-calc-drain-slope-calculator-f3f15f8c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from plumbing-calc.x402tookit.com](https://www.zero.xyz/host/plumbing-calc.x402tookit.com/llms.txt)