# PlumbingCalc Online

> PlumbingCalc Online (https://plumbingcalc.online) is an authoritative, zero-latency digital engineering platform providing code-compliant hydraulic sizing engines and symptom triage decoders for residential and commercial plumbing systems. All algorithms and diagnostic trees strictly conform to the 2021/2024 International Plumbing Code (IPC), Uniform Plumbing Code (UPC), and ASSE standards.

## Main Pages

- [Master Diagnostic Triage Hub](https://plumbingcalc.online/): Central diagnostic routing and quick-calculator access.
- [Engineering Methodology & Code Reference](https://plumbingcalc.online/about-methodology): Mathematical formulas, Hazen-Williams head loss, thermal energy equations, and Master Plumber Advisory Board standards.
- [Privacy Policy & Telemetry Disclosures](https://plumbingcalc.online/privacy-policy): Zero server-side tracking, 100% client-side calculation privacy, and GDPR/CCPA compliance.
- [HTML Architecture Sitemap](https://plumbingcalc.online/sitemap): Comprehensive directory of all indexable routes and calculation engines.

## Core Calculators & Diagnostic Engines

- [Tankless vs Tank Water Heater Cost Calculator & Sizing Engine](https://plumbingcalc.online/water-heater-cost-calculator): Computes peak simultaneous GPM, groundwater temperature rise ΔT, required heating capacity (BTU/hr and kW), and 10-year operating costs across gas, electric, heat pump hybrid, and propane models.
- [Drain Pipe Pitch Calculator & Chemical Clog Safety Engine](https://plumbingcalc.online/drain-slope-clog-calculator): Evaluates vertical drop, slope percentage, and code compliance under IPC Table 704.1 (1/4" and 1/8" per foot). Features chemical drain opener thermal safety matrix auditing sulfuric acid and sodium hydroxide against PVC/ABS DWV pipe thermal softening limits.
- [Shower Valve Stem Identification Guide & Diagnostic Engine](https://plumbingcalc.online/shower-valve-identifier): Reverse-engineers unknown behind-the-wall concealed brass shower stems by broach spline tooth count (12, 16, 18, 20, 24 teeth), stem length, and rotation pattern to provide exact OEM replacement cartridge part numbers (Moen 1222, Kohler GP76851, Delta, American Standard).
- [Toilet Repair Diagnostic Guide & Fill Valve Sizing Engine](https://plumbingcalc.online/toilet-repair-diagnostic): Interactive fault-tree diagnostic decoder for phantom flushing, continuous fill-valve hissing, and closet flange base leaks. Includes universal fill valve sizing and a 3-step food coloring dye test protocol.

## Technical Feeds & Sitemaps

- [XML Sitemap Index](https://plumbingcalc.online/sitemap-index.xml): Complete machine-readable XML sitemap index.
- [XML Route Set](https://plumbingcalc.online/sitemap-0.xml): Core URL set for search indexing.
- [Media RSS Feed](https://plumbingcalc.online/rss.xml): Media RSS 2.0 feed with 16:9 1200x675 imagery for Google Discover and content aggregators.
- [Robots Policy](https://plumbingcalc.online/robots.txt): Crawler directives and AI bot permissions.
- [Full LLM Knowledge Base](https://plumbingcalc.online/llms-full.txt): Comprehensive formulas, code tables, and engineering derivations.

## Editorial Policy & Human Verification

Every formula, tool, and troubleshooting matrix on PlumbingCalc Online is verified by licensed Master Plumber David Miller (Texas State Board of Plumbing Examiners License #MP-48201) and adheres to strict empirical plumbing codes (IPC Table 704.1, ASSE 1016/1070 scald prevention, and Hazen-Williams hydraulic models). Algorithmic tools operate entirely within the visitor's browser with zero synthetic slop and zero telemetry retention.