White Chalky Buildup in Drain Pipes Explained

Is your shower drain slow to empty? Do your sinks take forever to drain after washing dishes? If you've noticed white crusty mineral deposits in and around your plumbing fixtures, you're dealing with annoying calcium buildup.

Hard water is the usual culprit behind white mineral deposits that coat the insides of pipes, clog drains, and calcify around faucets. Understanding what causes this buildup and learning how to remove it can save homeowners tons of frustration and money on plumbing repairs.

What Causes White Calcium Buildup in Pipes?

White scale that collects in pipes and plumbing fittings is caused by minerals in hard water. The two main offenders are calcium and magnesium. However, other minerals like potassium and sodium can also precipitate out of the water and leave behind white residue.

Water hardness varies by geographic location based on the mineral content of the local water supply. Areas with high concentrations of dissolved rocks and minerals in groundwater tend to have harder water. The most common sources of hard water minerals are:

• Limestone deposits
• Sedimentary rocks
• Sea salts
• Calcium and magnesium sulfates
• Calcium and magnesium carbonates

Hard water minerals are soluble while the water is hot. But as the water cools in pipes and plumbing fixtures, the minerals lose solubility and precipitate out as white scale. Calcium carbonate is the main component of the grainy mineral deposits.

In addition to minerals naturally present in water, certain conditions can cause calcium and other minerals to come out of solution and leave behind buildup:

• pH fluctuations causing unstable water
• Sudden changes in water temperature
• Chemical changes from metal pipes and tank corrosion

Signs of Calcium Buildup in Plumbing

How can you tell if white mineral deposits from hard water are causing problems in your home's plumbing system? Here are some of the most common signs of calcium and magnesium buildup:

• White scale around faucets and showerheads
• Cloudy mineral residue on dishes
• Stiff laundry and white stains on clothes
• Clogged drains and pipes
• Reduced water flow from faucets
• Bathtubs and sinks take longer to drain
• Spotty glasses washed in dishwasher
• Water spots on kitchen and bath fixtures

Damage and Problems Caused by Calcium Buildup

If left unchecked, buildup of calcium scale and mineral deposits can cause serious damage over time. Here are some of the most common issues caused by hard water residue in plumbing:

• Corrosion of pipes and plumbing fixtures
• Clogged drains and restricted water flow
• Leaky plumbing from buildup wearing down seals
• Spotty dishes and laundry not getting clean
• Decreased water pressure
• Noisy pipes and water hammering sounds
• Dripping faucets from calcification at spouts
• Reduced efficiency of water heaters

In extreme cases, calcium scale buildup can completely block pipes and damage plumbing fixtures. The gradually increasing calcium deposits act like sandpaper wearing away at pipes. Flaking buildup can break loose and create obstructions.

How to Remove Existing Calcium Buildup

Dealing with hard water residue in pipes and plumbing requires removing existing scale buildup and taking steps to prevent future deposits. Here are some safe, effective methods for clearing clogs from calcium accumulation and descaling plumbing fixtures.

Baking Soda and Vinegar

A homemade drain cleaner made with baking soda and vinegar can dissolve mineral deposits to unclog drains. The chemical reaction between the acidic vinegar and alkaline baking soda releases carbon dioxide bubbles that break up calcium scale.

For sink drains, slowly pour 1/2 cup baking soda down the drain followed by 1 cup vinegar. Cover the drain opening with a stopper or rag to contain the fizzy reaction. Allow it to sit for 5-10 minutes before rinsing with hot water.

For shower drains, use 1 cup baking soda and 2 cups vinegar. Repeat treatments weekly to keep drains clear.

Boiling Water

Boiling water is an easy way to loosen calcium scale and clear debris from bathroom sink drains. Boil a kettle full of water and slowly pour it down the drain. The hot water melts and dissolves some of the minerals causing clogs.

For especially narrow or clogged drains, use a funnel to concentrate the flow of boiling water directly into the drain opening. Let it sit for 10-15 minutes before flushing with cold water.

Salt and Lemon Juice

The citric acid in lemon juice dissolves calcium carbonate deposits. For a natural drain cleaner, squeeze the juice from 5-6 lemons into a saucepan. Add 1 cup of salt and 2 quarts of water. Bring the solution to a boil, then let cool slightly before pouring down the clogged drain.

Leave it for an hour, then flush with hot water. The acidic lemon juice and abrasive salt crystals will help scrub away mineral buildup.

CLR Calcium Remover

CLR is a commercially available calcium, lime, and rust remover. It uses lactic acid to break down and dissolve mineral deposits from hard water. Pour 3-4 ounces of CLR directly into clogged drains, let sit for 5 minutes, then rinse.

For showerheads and faucets, soak the removable parts in a basin of CLR to dissolve calcium scale. Rinse thoroughly afterwards.

Preventing Future Calcium Buildup

Getting rid of existing calcium deposits is only half the battle. To avoid ongoing clogs and scale buildup, you also need to address the underlying cause - hard water.

Here are some ways to prevent future mineral deposits on plumbing fixtures and inside pipes:

• Install a water softener system to reduce water hardness
• Replace metal pipes with plastic PEX piping
• Use a scale inhibitor like phosphate or polyphosphate
• Install sink strainers and shower drain catchers
• Set water heater temperature below 140degF
• Use an acidic cleaner weekly in problem drains
• Replace old plumbing fixtures prone to mineral buildup

A whole house water softener is the most effective solution for controlling hard water problems. Water softeners use an ion exchange process to remove the calcium and magnesium ions that cause limescale buildup and replace them with non-scaling sodium ions.

When to Call a Plumber for White Buildup

For serious clogs and severe calcium deposit accumulation, a professional plumber may be needed. Here are some signs it's time to call for drain cleaning help:

• Drains are completely blocked with no water able to pass
• Persistent buildup returns shortly after removing
• Calcium deposits extend into main sewer lines
• Scale buildup has damaged pipes or fixtures
• You rent an apartment and cannot install a water softener

Plumbers have high-pressure water jets and snaking tools to mechanically clear mineral deposits and follow up with chemical treatments to prevent recurrence. They can also inspect your entire plumbing system to check for damage from scale accumulation.

FAQ About White Calcium Buildup

Calcium and magnesium deposits from hard water are not toxic or dangerous. However, buildup can damage plumbing, clog pipes, and bind up water-using appliances over time.