How Fast Does Acidic Water Damage Your Plumbing? (And Is It Too Late to Fix?)

Caller "I called a plumbing company. I think he said the pH was 2."

Aidan "A 2 on the pH scale is something that in 32 years I've never seen. The lowest we treat is 3.67. If you had copper pipes, there wouldn't be anything left."

She was in Connecticut. I told her to pick up a home test kit at Lowe's or Home Depot and check the number herself. Most calls about acidic water have the same three parts: a pH number, copper pipes, and the question of how long before something lets go. Here is what I tell people.

What acidic water does to copper pipes

Acidic water is water with a pH below 7.0, and on a private well it is usually caused by the local geology: rain that picks up carbon dioxide and organic acids in the soil, then passes through rock that has no limestone to buffer it. It comes out of the tap clear, and most people never suspect it until something stains or leaks.

Acidic water dissolves a little copper off the inside of every pipe, every day, until the wall is thin enough to leak. As the water passes through, it starts to create channels, and as the channels get thinner and thinner, you eventually get a pinhole leak. The outside of the pipe looks fine the whole time.

The copper ends up in your water before it ends up on your tub. Of the acidic wells my customers have had lab-tested, about one tap in six had more copper in the water than the EPA allows (its limit, called the action level, is 1.3 parts per million, or ppm). At a neutral pH it is about one tap in a hundred.

How long before you see real damage

On camera I put it at 6 to 18 months before you start seeing real damage, depending on your pH and how much water you use. That is the usual window, not a guarantee. Four things can make it sooner or later.

Your pH. The lower the number, the faster it goes. The wells I see up and down the East Coast average around 5.5, and the lowest I have ever treated was 3.67. Mild is not safe: I have had a 6.49 already staining a shower floor, and a buyer whose pH "was just slightly acidic" wrote that it "was still causing corrosion and staining."

The grade of your copper. Not all copper pipe has the same wall. I have had people go twenty-odd years on a well before the first green haze showed on the shower tile, and the reason is usually a heavier grade of copper that took that long to start breaking down. I have had 1960s houses call with only a little blue staining after all those years.

Hot or cold. The hot lines and the water heater fail first, every time. There is a section on that below.

How much water you run. A family of five pushes far more acidic water past the same pipe in a year than a retired couple does, so the same pH does more work in the busy house.

If all you have is a plumber's word, or a strip that turned orange, get a number first. A strip tells you acidic or not; a lab test gives you the pH to size the tank by. The lead section below says why the lab test is the one I point people to.

Two minutes on camera: what the water does to copper and where the 6 to 18 month window comes from.

Hard water is a different problem

Hard water does not eat pipes; it coats them. The white crust on a faucet and the scale in a water heater are calcium coming out of the water and building up inside the plumbing and the water-using appliances, narrowing things over years instead of thinning them. Acidic water does the opposite: it takes metal off the wall. A well can have both, and a neutralizer adds a little hardness while it fixes the pH, which is why the lab report shows pH and hardness side by side. If your problem is scale, the page you want is hard water vs. soft water.

The signs in the order they show up

Stains come first, then the fittings and the water heater, then the pinholes. Find the row that looks like your house. The row tells you how far along the damage is, and the last column is what I would do this week.

Ask Aidan

Not sure which row is yours?

Text me your pH and a photo of the stain, the fitting or the pipe. I'll tell you where you are on the clock and what to do first.

Text Aidan443-277-2204 Call800-460-5810Aidan

8 AM to 5 PM Eastern, seven days a week. A real person, usually Aidan.

Why the hot water side goes first

Heated acidic water is four to five times more aggressive than cold water, so the water heater and the hot lines take the damage before the cold side does. Inside the heater it wears away the bottom of the tank and eats the elements, and the elements are a cost to replace before the tank ever leaks.

I have seen houses where the bottom blew out of the hot water heater and flooded the basement. Long before that, the heater tells you: a small weep at the bottom, or a blue-green crust around the brass drain valve. The fittings go the same way; people call me after the whole faucet came off in their hand. If you are deciding how urgent this is, look at the heater and the hot lines, not the cold ones. The water heater page goes through what to check.

Is it too late once pipes leak?

No. Once a neutralizer raises the pH, the corrosion virtually stops. People ask me that exact question after the first pinhole, and the answer is the same at the first leak or the fifth.

What it cannot do is put copper back on a wall that has already thinned. A section that is thin stays thin, and a plumber replaces what has opened. What changes is that you stop chasing leaks. There may be thin spots left, especially on the hot side, but the next section is no longer on the clock, and you are not tearing walls down every year.

How you know it worked is the pH at the tap. Calcite alone settles the water near 7. For a very low pH I blend in FloMag, a stronger mineral, and the water lands between 7 and 8. Buyers who retest send in numbers like 5.2 to 7.2 and 6.5 to 7, the new staining stops coming back, and one buyer with a plumber-installed tank wrote that it "started working the same day." Their before-and-after numbers are in the buyer table below.

Plastic PEX pipe does not stop the corrosion

Switching to plastic PEX pipe takes the copper out of the walls. The water is still acidic. A caller in Pennsylvania with a 1975 house had replaced every copper line after pinholes and "that green stuff." He had tried to clean the green off a toilet valve, it broke off in his hand, and it flooded the bathroom. So he re-piped the house in PEX, the plastic pipe, with brass fittings, and by the time he called me, the brass fittings were getting a little green on the outside.

What I told him: you still need to protect your hot water heater, your water-using appliances like the dishwasher and washing machine, and the things in the walls you couldn't get to. PEX is plastic; almost everything it connects to is brass or copper. Three buyers over six years wrote me the same story from the other end. One had flooding inside the walls before a water test showed the acid had eaten the bronze fittings on his PEX system (his review is in the buyer table below). One found "the brass fittings on my Pex waterlines were all corroding" at a pH of 5.5. One had leaks at three PEX brass joints at a pH of 6.2. The pipe changed. The fittings, the heater and the appliances were still on the clock.

Old copper joints put lead in the water

Copper joined before 1986 can put lead in the water, because up until 1986 plumbers were allowed to use lead solder to join copper pipe. The lead does not come from the well. It comes from the joints, and acidic water pulls it out the same way it pulls the copper. The EPA's action level for lead is 0.015 ppm, dropping to 0.010 in November 2027.

You cannot see lead or taste it, and a hardware-store strip does not measure it, which is why the pointer on this page is the certified lab test. Both read highest on the first water out of the tap after it has sat in the pipe a while. This month a 5.9 well in a hundred-year-old house read 4.6 ppm of copper on that first glass, three and a half times the EPA limit, and about 0.5 after the tap ran. That is metal sitting in your pipes, not in your well, and correcting the pH is what stops it dissolving in the first place. If drinking it is your worry, are you drinking acidic water covers what the numbers mean for your family.

If your only number is a strip or a plumber's word: certified lab test, $199

A lab test shows copper and lead too

One certified lab test, mailed to you, run by an accredited lab, reports your pH, the copper and lead already at your tap, and the hardness that decides whether a softener belongs behind the neutralizer.

Get the certified well water test

53 contaminants. Results reviewed by Aidan, in plain English. On city water, use the city water test.

The cost of waiting vs. fixing the water

If you do not put the neutralizer in as soon as you find out you have acidic water, you are going to incur damage: a pipe breaking inside a wall, a washing machine, a dishwasher, a water heater. Any one of those can run into thousands of dollars. Repairs almost always cost far more than the tank that would have prevented them.

The tank is $1,495 shipped for the 2.5 cubic foot non-backwashing model, $1,395 for the 2.0, and $1,295 for the 1.5. What ships is the tank, the control valve with the bypass pre-installed, and the calcite in separate bags that are loaded into the tank at install; drain tubing is not needed on this design because it does not backwash, and it uses no electricity. Which size is yours depends on your pH and how many people are in the house: the sizing guide walks through it, and the how-it-works page shows the inside of the tank.

We recommend installation by a licensed plumber, and I support your plumber by phone at 800-460-5810. A plumber typically finishes it in two to three hours; one buyer's took about three and had to cut and refit the copper leading to the tank. All of the non-backwashing sizes are on the acid neutralizer collection.

What buyers saw after raising their pH

Reviewer names appear as the buyers wrote them; every review below is a verified purchase.

Frequently asked questions