Guides
Plain-English background to the numbers behind the calculators — from what it costs to repipe a house and how to size a water heater, to how to size supply pipes, drains, vents and gas lines, and what low-flow fixtures really save.
How Much Does It Cost to Repipe a House?What drives the cost to repipe a house, how PEX and copper compare, and how to turn a plumber quote into a per-fixture number you can sanity-check.Tank vs Tankless Water Heater: Which Is Cheaper?Tank and tankless water heaters compared on upfront cost, energy use and lifetime spend, with a clear way to run the numbers on your own figures.What Size Water Heater Do I Need?Size a storage water heater by peak-hour demand and first-hour rating, not by household size alone — with a worked example and recovery-rate check.How to Size a Tankless Water HeaterSize a tankless water heater the right way: add up simultaneous GPM, find your temperature rise, and convert to the BTU/hr or kW the unit must deliver.How to Size Water Supply PipesSize water supply pipes with fixture units: total WSFU, convert to peak GPM on the Hunter curve, then read the pipe diameter that carries that flow.Low Water Pressure: Causes & How a PRV HelpsWhy water pressure drops — height, friction, clogged pipes and PRVs — and how to diagnose it with head and friction-loss math before you call a plumber.Drainage Fixture Units & Drain SizingWhat drainage fixture units (DFU) are, how to total them, and how they set the minimum drain pipe size — with a worked example and reference bands.Proper Drain Slope (1/4 Inch per Foot)The right drain slope — 1/4 inch per foot for smaller pipe, 1/8 for larger — why too flat and too steep both clog, and how to calculate total fall.How to Size a Plumbing VentWhy drains need vents, how to size a vent from fixture units and developed length, and how trap-arm limits keep the trap seal from siphoning away.How to Size a Gas LineHow gas lines are sized: total appliance BTU load, convert to CFH, and read the pipe diameter for your longest run — planning only, gas work is licensed.How Much Does a Plumber Cost?How plumber pricing works — hourly rates, trip fees, flat-rate vs time-and-materials, parts — and how to sanity-check a repair quote on your figures.How Much Water Do Household Fixtures Use?Where household water actually goes — toilets, showers, faucets, laundry — with typical flow rates and how to estimate daily use and shower cost.Low-Flow Fixtures: Real Water & Money SavingsWhat low-flow toilets, faucets and aerators actually save in water and dollars, how to run the numbers on your own bills, and when an upgrade pays off.Dripping Faucet & Running Toilet WasteHow much water a dripping faucet or running toilet really wastes, what it costs per month, and how to find and stop the silent leaks driving up your bill.