The shower used to sting a little. Now it fans out sideways, half the holes are plugged with white crust, and the pressure drops off when someone runs the kitchen tap. Your glasses come out of the dishwasher cloudy no matter what detergent you buy, the kettle has a gray shell inside it, and the water heater in the garage has started ticking and popping when it fires.
That is hard water. In Corona and across most of Riverside County, tap water routinely tests somewhere between 10 and 20 grains per gallon — roughly 170 to 340 parts per million of dissolved calcium and magnesium. Anything above 7 grains is considered hard. We are well past that, and the minerals do not stay dissolved forever. They plate out on anything warm, anything narrow, and anything that holds still.
Work through the causes below in order. The first three cost nothing but twenty minutes. The last ones are the reason licensed plumbers exist.
1. Clogged aerators and showerheads (free to check, 15 minutes to fix)
This is the most common cause of “low water pressure” calls in hard-water areas, and it is almost never actually low pressure. Scale builds up inside the aerator — the little screened insert threaded into the tip of every faucet — and inside the rubber nozzles of a showerhead.
How you recognize it: the problem is at one fixture, not the whole house. Flow is weak or sprays crooked. If you unscrew the aerator by hand and the flow suddenly gushes, you have found it.
The fix: unthread the aerator (a rag and pliers if it is stuck), soak the screen and housing in white vinegar for an hour, brush the grit out with an old toothbrush, reassemble. Showerheads get the same treatment — a sandwich bag of vinegar rubber-banded over the head overnight works fine. Replacement aerators run $4 to $10. A decent showerhead is $25 to $60. Do this once a year here and you will notice the difference.
2. A water heater full of sediment (free to check, $150–$350 to have flushed)
Calcium falls out of solution fastest where water is heated, so your tank water heater is the scale collection point for the whole house. On a gas unit the sediment settles on the bottom of the tank, the burner fires through it, and steam pockets pop underneath — that is the ticking and rumbling you hear. Electric units bake scale onto the lower heating element until it fails.
How you recognize it: hot water runs out faster than it used to, the tank makes noise on startup, or you get sandy white grit in the aerator screens you just cleaned. Hot-only pressure problems point here almost every time.
What fixing it involves: attach a hose to the drain valve at the bottom of the tank, shut off the cold inlet, open a hot tap somewhere in the house, and drain several gallons until it runs clear. Homeowners can do this safely. Two cautions specific to older tanks: plastic drain valves clog with the very sediment you are trying to remove, and a tank that has never been flushed in eight years can start weeping at the valve afterward. If the valve will not reseat, you need a plumber that day. A professional flush, including swapping a failed drain valve for a brass one, typically runs $150 to $350.
3. Angle stops and shutoff valves seized with scale
Every toilet and sink has an angle stop — the small chrome valve on the supply line behind the fixture. Multi-turn stops that sit untouched for a decade grow scale on the stem and the washer. When you finally need to close one during a leak, it either will not turn or it will not seal.
How you recognize it: turn each stop in your house a half turn and back, once a year. Anything that squeaks, binds, or drips at the stem packing after you move it is on borrowed time. The main house shutoff deserves the same test.
The fix: replacing an angle stop is a 20-minute job for a plumber, usually $125 to $250 per valve, less per valve if several are done in one visit. Quarter-turn ball-type stops resist scale far better than the old multi-turn compression style and are worth the upgrade while someone is already under the sink.
4. Scaled and corroded galvanized supply lines
Plenty of housing stock in Riverside, Corona, and the older parts of Norco was plumbed in galvanized steel before copper took over. Hard water attacks galvanized pipe from the inside: the zinc coating wears away, the steel rusts, and the rust plus mineral scale narrows a 3/4-inch pipe to the effective diameter of a drinking straw.
How you recognize it: whole-house pressure loss that got worse gradually over years, rusty or yellow water after the house sits unused, and visible threaded gray pipe at the water heater or in the crawlspace. Galvanized supply typically gives 40 to 60 years of service, so anything from the 1960s or earlier is at or past the end.
What fixing it involves: repiping. That means running new PEX or copper from the main to every fixture and abandoning the old lines. Whole-house repipes typically run $4,000 to $15,000 nationally. What drives the number up: slab foundations that force lines through the attic and down interior walls, two-story layouts, stucco and lath that has to be opened and patched, and the drywall repair and repaint that follows. Repiping is not a DIY project — it is behind walls, it requires a permit and inspection in most Riverside County jurisdictions, and a mistake means a slow leak inside a wall cavity you will not find for a year.
5. Failed anode rod and a tank at the end of its life
The anode rod is a sacrificial metal rod threaded into the top of your water heater. It corrodes on purpose so the steel tank does not. In hard, mineral-rich water that rod can be consumed in three to five years instead of the usual six, and once it is gone the tank lining starts eating itself.
How you recognize it: rotten-egg smell in the hot water only, rusty hot water, or moisture on the floor around the base. A tank water heater lasts 8 to 12 years here; scale shortens that. Tankless units go closer to 20, but they need descaling every one to two years in this water or the heat exchanger clogs and throws error codes.
Anode rod replacement is a $150 to $350 job and buys real years. Once the tank itself is leaking, it is done. Replacement typically runs $1,500 to $3,000 for a standard 40- or 50-gallon gas tank, and $3,500 to $6,500 for tankless with the gas line and venting work that conversion usually requires. Water heater swaps require a permit in most local jurisdictions, and current code often adds items to the bill: seismic strapping, a thermal expansion tank, a drain pan with a routed drain line, and sometimes a new flue or a larger gas line. Anything involving a gas connection or combustion venting belongs to a licensed plumber. Carbon monoxide is not a learning opportunity.
6. Slab leaks and pinholed copper under the foundation
Copper under a slab sits in soil, sometimes in contact with concrete, carrying mineralized water. Over decades it develops pinhole leaks. Because the pipe is encased in the foundation, the water has nowhere to go but sideways and up.
How you recognize it: a warm spot on the floor, the sound of running water when every fixture is off, unexplained damp carpet edges, a foundation crack that stays wet, or a water bill that jumps 30 percent with no change in habits. Shut every fixture and watch the leak indicator dial on your meter — if it creeps, water is going somewhere.
Slab leaks need electronic leak detection and either a spot repair through the concrete or a reroute overhead. Typical cost runs $1,500 to $6,000 depending on access and whether the reroute goes through finished ceilings. This is pro-only work: locating it wrong means jackhammering the wrong three feet of your living room floor.
7. Drain and sewer scale in older cast iron
Hard water leaves deposits on the drain side too, and in cast-iron waste lines the scale combines with rust tubercles and grease to narrow the pipe. Homes built before the mid-1970s often still have cast-iron drains, which last roughly 50 to 75 years.
How you recognize it: multiple fixtures draining slowly at once, gurgling from a tub when the toilet flushes, or sewage odor near a floor drain. One slow sink is a P-trap clog you can handle with a plunger or by pulling the trap. Several at once means the problem is downstream in the main line.
A plumber will pull the cleanout cap and run a camera, then either cable the line or hydro-jet it. Camera inspection typically runs $200 to $600; jetting $350 to $900. Sewer line replacement runs $3,000 to $12,000. Do not open a sewer cleanout yourself unless you are prepared for what comes out under pressure, and never pour drain chemicals into a cast-iron line — they accelerate the corrosion that caused the restriction.
What can wait, and what cannot
Can wait a week or two: cloudy glassware, a crusty showerhead, a single slow-draining sink, a water heater that rumbles but still delivers hot water, spotting on fixtures. Annoying, not destructive.
Cannot wait past today: water on the floor near the heater, a warm or wet spot on a slab floor, the meter dial turning with everything off, sewage backing up into a tub or shower, or any drip inside a wall or ceiling. In those cases close the main shutoff at the street side of the house or at the meter, and if the trouble is at the water heater, also close the cold inlet valve on top of the tank and turn the gas control to “off” or kill the breaker. Then call.
When to stop checking and call
Call a licensed plumber if you have cleaned the aerators and flushed the heater and pressure is still weak at more than one fixture. Call if hot water runs out in under ten minutes with a tank under ten years old. Call the same day if you see rusty water, smell sewage indoors, hear water running with every tap closed, or find any moisture around the base of the water heater or on a slab floor.
And if you are already spending money on the symptoms — new showerheads every two years, a second aerator soak in six months, a failed heating element — ask about a whole-house softener or a scale-inhibiting conditioner at the same visit. Installed systems typically run $1,200 to $3,500 with a drain connection and a bypass loop. In water this hard, that math tends to work out.
Featured image: Photo by Orhan Akbaba on Pexels.
