What Hard Water Does to Your Plumbing

What is hard water, and how hard is yours?

Hard water contains high levels of dissolved calcium and magnesium. Penn State Extension uses this scale:

Classification	Grains per gallon	Parts per million
Soft	Less than 1.0	Less than 17
Slightly hard	1.0 to 3.5	17 to 60
Moderately hard	3.5 to 7.0	60 to 120
Hard	7.0 to 10.5	120 to 180
Very hard	Above 10.5	Above 180

Do not rely on a figure from a salesperson. Numbers quoted online for Houston vary widely, so get yours from your own supplier or a test. The EPA says a Consumer Confidence Report tells you about the drinking water in your area, and it offers a lookup tool for finding yours. The name on your water bill tells you whose report to read.

That point matters in Aldine, which is unincorporated, because your supplier may not be a city. Test strips from a hardware store give a quick second check at the tap.

How to read the number you find

Reports and test kits do not all speak the same unit. Most water reports list hardness in parts per million, and softener sellers quote grains per gallon. Divide parts per million by 17 to convert. A report showing 170 ppm means about 10 grains, which sits near the top of the hard band in the table above.

Hardness is a nuisance measure and not a health limit, so some reports bury it in a secondary table or leave it out. If yours does, call the supplier and ask. Test at a cold kitchen tap ahead of any softener or filter. Supply also changes the answer. A home on a well or a district well can test very differently from a house across the road on treated surface water.

Hard water effects on plumbing pipes

Scale narrows the pipe from the inside, slowly. Calcium carbonate is the main component of scale, and it forms deposits on pipe interiors that restrict flow, according to Wikipedia's hard water entry.

The effect is rarely sudden. You may see pressure drop at one fixture first, because small openings choke before big ones. Hot lines tend to scale up faster than cold, as heat drives minerals out of solution.

Older galvanized pipe has it worst, as its rough, corroded inner wall catches minerals. If pressure has fallen throughout an older house, scale may be only part of the story, and it is worth asking about the pipe itself.

What does scale do to a water heater?

The water heater takes the biggest hit. Heat is what makes scale form, so the bottom of a tank and the elements inside it collect minerals first.

• Sediment settles at the bottom and insulates water from the burner
• Electric elements get coated and may burn out sooner
• Popping or rumbling sounds come from water trapped under sediment
• Recovery gets slower, so hot water seems to run out sooner
• Tankless exchangers can block and shut down from overheating

On tankless units, the narrow passages make this worse. Manufacturers commonly call for water testing, treatment, and yearly descaling through service valves. Wikipedia notes that scale deposits slow heat transfer and lower heating efficiency in boilers, and the same physics applies to a home heater.

A regular flush helps a tank. Our guide on no hot water covers the warning signs, and a water heater repair can often deal with a coated element or a stuck drain valve.

Is that crust scale or corrosion?

Check the color and try vinegar before you buy anything. Crust on a fixture can come from different problems, and only one of them is hardness:

What you see	What it usually is	Quick test or next step
White or chalky crust	Hard water scale	Fizzes and softens in white vinegar
Blue-green stain	Copper corrosion	Ask about the pipe and the water's pH
Orange or brown stain	Rust from iron or steel pipe, or the tank	Run hot and cold apart to find the side
Black specks at the aerator	Failing rubber parts or sediment	Check the supply hoses and washers

The color matters because a softener fixes only the first row. Blue-green or rust stains point to the pipe, and that repair is a different job.

Which fixtures and appliances show it first?

Look at the small openings. These are the early warning signs around the house:

• White crust on faucet aerators and shower heads
• Toilet fill valves that stick or run on
• Weak spray from shower heads
• Spots on glassware after the dishwasher
• Soap that will not lather and leaves film on skin
• Detergent residue in the washing machine

Soaking an aerator or shower head in white vinegar will clear most of the crust. Turn off the water and take photos of the parts before you remove them, so they go back the right way.

A yearly routine for scale

A short calendar beats a big repair. Here is a routine that fits most homes with hard water:

When	Job	Why it helps
Monthly	Wipe faucet bases and check aerators	Small openings show scale first
Every few months	Soak shower heads	Keeps spray and pressure up
Yearly	Flush the tank	Clears sediment from the bottom
Yearly	Descale a tankless unit, as the manual directs	Protects the heat exchanger
Yearly	Service the softener and check its settings	Keeps treatment matched to your test
Every few years	Have the anode rod checked	Softened water can wear it faster

Our team's advice on when a softener earns its keep

Decide from your test result and your symptoms. Our team's general advice is that a water softener makes the most sense when the number is high and you are already seeing the damage.

• Test first: hard or very hard water with visible scale is the clearest case.
• Protect the heater: a tankless unit benefits most, since it is so sensitive to scale.
• Plan for upkeep: a softener needs salt, and Penn State says the brine supply has to be maintained.
• Look at demand-control models: timed units regenerate on a schedule and can waste water and salt.
• Think about sodium: softening adds about 7.5 milligrams per quart for each grain removed, which matters on a low-sodium diet.

Softened water is not always what you want at every tap. Ask about keeping a cold line unsoftened at the kitchen sink. If taste or chlorine is the real complaint, look at water filtration instead.

Be careful with magnets and other no-salt gadgets. Those devices do not take calcium and magnesium out of the water, so ask the seller for independent test results on scale before you spend money. Location matters as well. A softener needs a drain, a power outlet and a plumbing loop near where the main line enters, and a slab home may have that loop in the garage or nowhere at all.

What to do about hard water this month

Start small and work up. Find your hardness number, then clean an aerator to see how much scale is really there. Flush the water heater if it has not been done in a while.

If the numbers and the symptoms agree, talk to a plumber about treatment. Scale is slow and quiet, and it costs you a little every day. You will get a clear, upfront quote after a look at your setup.