Plumbing Calculators
21 calculators21 free calculators for plumbing homeowners.
Sizing and schedules
How big a system you need and how often it needs service.
Water Heater Size
Find the right water heater size for your home: the tank your busiest hour of hot water needs, or the tankless flow your winter tap water calls for.
Septic Tank Size
Find the septic tank size your house needs by its number of bedrooms, the minimum most codes set, and what a garbage disposal can add.
Septic Tank Pumping Frequency
Find out how often to pump your septic tank, based on EPA pumping-frequency data for your tank size and household. Accounts for a garbage disposal, and gives your next pump-out due date.
Water heaters and water treatment
Replacing the heater, choosing a type, and treating the water.
Water Heater Replacement Cost
Estimate the cost to replace your water heater by type — gas or electric tank, tankless, or heat-pump (hybrid) — scaled to your household size and install complexity, with current rebate and efficiency guidance.
Tankless vs. Tank Water Heater
Compare a tankless water heater to a traditional storage tank — upfront cost, annual energy savings, payback, and 20-year total. See why gas tankless pays back slowly but still often wins over 20 years, and why electric homes are usually better off with a standard tank.
Whole-House Water Softener Cost
Estimate the installed cost of a whole-house water softener — salt-based, dual-tank, or salt-free — and the grain capacity your household actually needs, sized from your household size and water hardness.
Water Filtration System Cost
Estimate the true cost of a home water filtration system — pitcher, reverse osmosis, whole-house, or softener — including the filters and salt you buy for years, not just the sticker price.
Well Water System Cost
Estimate the yearly cost of owning a private well — annual water testing, treatment consumables, periodic inspection, and the pump reserve most owners forget until the pump fails.
Pipes, drains, septic and sewer
The lines in the walls and under the yard.
House Repiping Cost
Repiping a house costs $1,500–$15,000+ depending on size and pipe material — PEX runs roughly half of copper. Price your home, compare the materials, and see why polybutylene and galvanized pipes make this a when-not-if project.
Sewer Line Replacement Cost
Replacing a sewer line costs $50–$250 per foot — $2,000–$10,000 for a typical 40-ft run. Compare a traditional dig against trenchless pipe bursting and CIPP lining, and see when a repair beats replacing.
Hydro Jetting vs. Snaking Cost
Compare hydro jetting vs. snaking a clogged drain — per job and over 5 years. Snaking is cheaper today ($150–$500), jetting cleans the pipe for 2–3 years ($600–$1,400). See which wins for your clog.
Water Main Break Repair Cost
How much does it cost to fix a water main break? $400–$1,500 to spot-repair the line to your house, or $2,000–$12,500 to replace it. Compare both by line length and method — and see which one your pipe's condition actually calls for.
Septic System Replacement Cost
Replacing a conventional septic system costs $3,500–$8,500 plus $1,000–$2,000 in permits and testing — and a failed drain field alone runs $3,000–$15,000. Price your system type and see what your soil decides.
Sump Pump Replacement Cost
Estimate the cost to replace a sump pump in an existing pit — by pump type and horsepower, DIY or professional install, plus battery backup, water alarm, and check valve.
Gas Line Installation Cost
Running a new gas line costs $15–$25 per foot for simple runs — $500–$1,200 for a stove, $400–$900 for a dryer, $600–$1,300 for a grill. Price your appliance or your exact footage, permit included.
Greywater System Cost
Estimate the cost to install a greywater system — reusing laundry, shower, and sink water for irrigation. See prices by system type (laundry-to-landscape, branched-drain, pumped/treated), complexity, and permit — and why greywater is a conservation move, not a fast money-saver.
Fixtures and appliances
Sinks, showers and what the appliances cost to run.
Plumbing Fixture Upgrade Cost
Estimate the cost to upgrade your plumbing fixtures — faucets, toilet, sinks, showerhead, shower valve, bathtub, or garbage disposal. Pick how many of each at standard or premium quality and get the installed cost (fixture + labor) per fixture and a total.
Kitchen Sink Replacement Cost
Estimate the cost to replace a kitchen sink by material (stainless, composite, fireclay) and mount type (drop-in, undermount, farmhouse). See why changing the mount type — the countertop or cabinet work — is the big hidden cost, with faucet and disposal folded in.
Shower Pan Replacement Cost
Estimate the cost to replace a shower pan, installed — by pan type (prefab acrylic/fiberglass base, solid-surface, or custom tiled), shower size, and whatever water damage is found under the old pan. See why the subfloor is the wild card.
Dishwasher Running Cost
Calculate what it costs to run your dishwasher — water, sewer, and electricity, per cycle and per year — and see how it compares with washing dishes by hand (running tap vs. two-basin).
Washer & Dryer Running Cost
See what it costs to run your washer and dryer — per load and per year — and compare standard-electric, heat-pump, and gas dryers side by side. Find the cheapest option for your rates and usage, and why washing cold saves the most.
About Plumbing Calculators
Plumbing problems are among the most expensive home repairs, often costing thousands of dollars when you call a professional without understanding what you actually need. The difference between a simple fix and a complete system replacement frequently comes down to knowing the right measurements and calculations upfront—whether that's pipe sizing for a new bathroom, water pressure requirements, drain slope specifications, or the actual cost of materials you'll need. Our plumbing calculators help you determine exactly what's required before you hire a contractor, which means you'll get accurate quotes, avoid unnecessary work, and make informed decisions about repair versus replacement.
Knowing these numbers also helps you understand if a contractor's recommendation makes sense or if you're being oversold. Most homeowners drastically underestimate water usage and oversize pipes, leading to low pressure and wasted money on materials and installation. Similarly, many people don't realize that drain lines must slope at precise angles—usually 1/4 inch per foot—or they'll fail repeatedly, becoming a recurring expense.
Our calculators handle the math that building codes require, from gallons-per-minute calculations to fixture unit counts that determine your main water line size. By running these numbers yourself, you'll enter any conversation with a plumber or contractor with confidence, know whether their proposed solution is reasonable, and have the data to get competitive bids.