Water that is more acidic than neutral, usually described by its pH, can slowly attack metal in your plumbing. The problem often shows up on fixtures and pipes long before anyone tastes it. Before you shop for a neutralizer or any other equipment, learn to read the clues your house is already giving you.
Look at the stains around the water
Blue-green or green staining around drains, faucet bases, toilet tank fittings and the bottom of sinks is a common sign that copper is dissolving somewhere upstream. Check whether the stain appears only on fixtures that get cold water, and whether it returns after you scrub it. Rust-brown staining points to iron or manganese, which is a different question with different treatment, so do not assume every stain has the same cause.
Check the copper and the water heater
Pinhole leaks in copper pipe, especially those appearing in several places over time, are worth investigating. So is a water heater that fails earlier than its warranty period suggests, or a sacrificial anode rod that looks badly used when it is inspected. A plumber can tell you what they see inside the tank, and you should ask them to note the condition in writing.
Notice taste and smell, with care
Some people describe acidic water as sour, flat or metallic. Metallic taste overlaps with several causes, so do not treat taste alone as proof. Use the taste as one clue that adds to the stains and pipe findings.
Get a lab test that reports pH
A dip strip from a hardware store can give a rough idea, but a certified laboratory result is more reliable. Ask the lab to report pH along with the other parameters it tests, and ask whether they measured the sample at the tap or at the source. Follow the sample collection instructions exactly, since a poorly collected sample can mislead you. Keep the report with its sample details so you can compare it with later results.
Ask what the test changes
Before you approve any equipment, ask the provider how the proposed solution depends on the pH result. Some corrosion control approaches add minerals or raise pH before the water reaches the plumbing, while others address a different problem entirely. A provider who recommends equipment without reference to your test result has not yet shown you the link between the problem and the fix.
What to do with the findings
Write down what you saw on the fixtures, what the water heater looked like, and what the lab reported. Bring those notes to any provider you consider. If the findings do not match what a provider claims, ask them to explain the difference before you pay for anything.