Hard Water Buildup
Updated February 20, 2026
White, chalky deposits on everything -- faucets, shower heads, glass doors, inside pipes and water heaters. Calcium and magnesium restrict flow, kill efficiency, shorten appliance life. About 85% of US homes have hard water.
Overview
High calcium and magnesium in the water. Not a health hazard (same minerals in supplements), but it wrecks fixtures, appliances, and pipes over time. The white buildup you see on faucets is limescale -- the same stuff forming inside your pipes, water heater, and dishwasher where you cannot see it. Under 3.5 GPG is soft, 3.5-7 moderate, 7-10.5 hard, above 10.5 very hard. Light buildup manages with vinegar. Persistent problems need a softener.
Symptoms
- White, chalky deposits on faucets, shower heads, and drains that return quickly after cleaning
- Cloudy spots on glass shower doors and dishware that will not wipe off -- etched mineral deposits
- Reduced flow from shower heads and aerators as deposits clog the openings
- Water heater takes longer or makes popping and rumbling noises -- scale insulates the element, killing efficiency
- Soap and shampoo will not lather. Film on your skin after showering.
- Laundry comes out stiff, faded, or gray -- hard water prevents detergent from dissolving and rinsing
Common Causes
- Geology of your water source -- groundwater passes through limestone, chalk, and dolomite, dissolving calcium and magnesium. Safe to drink, but the minerals precipitate out when heated or evaporated, leaving deposits.
- No softener installed -- most homes in hard water areas benefit from one, but many (especially older homes) were built without. Full mineral load hits every pipe, fixture, and appliance.
- Well water -- draws directly from aquifers with higher mineral content than treated municipal. Hardness ranges from moderate to extreme depending on geology, and nobody treats it before it enters your home.
- Municipal water that is naturally hard -- some cities treat for safety (chlorine, fluoride) but do not soften. Check your utility's annual report for hardness.
- Hot water accelerates scale -- heating causes minerals to precipitate faster. Water heater tank, elements, and hot pipes scale much faster than cold. Above 140 degrees dramatically accelerates it.
What You'll Need
How to Fix It
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Test Your Water Hardness
Know your number before choosing a treatment. Hardness test kit ($5-10, hardware store or online), test strips or titration. Cold tap water, follow kit instructions. Under 3.5 GPG is soft, 3.5-7 moderate, 7-10.5 hard, above 10.5 very hard. That number tells you whether cleaning is enough or you need a softener.
Tip: Municipal water? Check your utility's annual Consumer Confidence Report (free online). Includes hardness levels. Saves you the cost of a test kit. -
Remove Existing Buildup from Fixtures
Faucets: soak a cloth in white vinegar, wrap the fixture, rubber band, leave 1-2 hours. Vinegar dissolves calcium carbonate. Scrub with a toothbrush or non-scratch pad, rinse. Shower heads: unscrew and submerge in vinegar 2-4 hours (overnight for heavy buildup). Glass doors: spray undiluted vinegar, 15 minutes, non-scratch sponge. Heavy deposits vinegar cannot handle? CLR or a commercial lime remover.
Tip: Chrome and brushed nickel: vinegar or a product labeled safe for the finish. No abrasive cleaners or steel wool -- permanent scratches. -
Clean the Shower Head Openings
Reduced flow or uneven spray? Deposits clogging the nozzles. After the vinegar soak, poke through each opening with a toothpick, safety pin, or needle. Run hot water through before reinstalling to flush debris. Many modern heads have silicone nozzles you can wipe with your finger to dislodge scale.
Tip: Replacing the head? Choose silicone jet nozzles (marketed as easy-clean). Much easier to maintain in hard water than plastic or metal designs. -
Flush the Water Heater
Scale on the tank bottom and heating elements insulates against heat transfer -- heater works harder, costs more, dies sooner. Power off (gas or electric), cold supply off. Garden hose on the drain valve, run to a floor drain or outside. Open and let it empty. You will see white sediment and scale chunks. Once drained, briefly open the cold supply to flush more sediment. Close, refill, restore power.
Warning: The water is hot. Cool for several hours before draining, or handle the discharge carefully. Never stand in front of the drain valve when opening. -
Clean Faucet Aerators
Unscrew and disassemble. Mesh screen and flow restrictor both collect deposits. Soak in vinegar 30-60 minutes, scrub with a toothbrush, rinse. Heavily clogged and cleaning does not help? Replace -- $3-8. With the aerator off, run the faucet briefly to flush sediment from the supply line.
Tip: Every 3-6 months in hard water areas. One of the simplest and most effective maintenance tasks for good water flow. -
Consider a Whole-House Water Softener
Above 7 GPG, cleaning only manages symptoms. A whole-house softener is the real fix. Salt-based softeners use ion exchange to replace calcium and magnesium with sodium -- eliminates scale throughout the system. $500-2,500 installed. Salt-free conditioners (descalers, TAC systems) change the mineral structure so it does not stick. $300-1,500, no salt or drain needed, but less effective for very hard water.
Tip: Salt-based softener? Have the installer leave 1-2 GPG rather than softening to zero. Adequate scale prevention without the slippery feel some people dislike.
When to Call a Pro
Call a plumber for softener installation (requires cutting into the main line and adding a drain connection), if scale has reduced flow throughout the house and you need a pipe assessment, if the water heater drain valve is clogged, or if you are on a well and need comprehensive testing. A plumber or water treatment specialist can test, recommend the right capacity, and install correctly.
Prevention Tips
- Above 7 GPG? Water softener. Single most effective prevention for the entire system.
- Vinegar cleaning on faucets, shower heads, and aerators every 1-3 months. Remove deposits before they get heavy.
- Flush the water heater annually. Removes scale from the tank bottom, extends lifespan, maintains efficiency.
- Water heater at 120 degrees, not 140. Lower temperature significantly reduces scale formation rate.
- Rinse aid in the dishwasher for mineral spots. Monthly vinegar cycle to clean the interior.
- Squeegee glass shower doors and chrome fixtures after each use. Prevents water droplets from evaporating and leaving deposits.