What are expert tips for corrosion & water quality monitoring?

Test your water annually if you're on a well. Municipal water is tested by the utility, but your pipes can still affect what comes out of the tap. Blue-green stains don't mean your water is unsafe -- but they do mean your pipes are slowly being eaten away. If you notice a metallic taste in your water, run the tap for 60 seconds before drinking. The metals concentrate in standing water. When repiping, PEX is more resistant to corrosive water than copper and costs less to install.

What mistakes should I avoid with corrosion & water quality monitoring?

Ignoring blue-green stains -- they're a visible warning that copper corrosion is active. Connecting copper directly to galvanized steel without a dielectric union. The galvanized pipe will corrode rapidly at the joint. Assuming city water can't be corrosive. Municipal water can still have low pH or high chlorine. Waiting for pinhole leaks before addressing corrosive water. By then, the pipes have been thinning for years.

Corrosion & Water Quality Monitoring

Maintenance Guide Intermediate Ongoing monitoring $15-$50 for water testing / varies for treatment

Created by Ryan Pietrzak Illinois Licensed Plumber · In the plumbing industry since 2009

Updated February 20, 2026

Key Takeaway

Your pipes are slowly corroding from the inside right now. That's normal -- all metal pipes do it. The question is how fast. Aggressive water chemistry accelerates corrosion and can turn a 50-year pipe system into a 20-year one. Understanding your water quality and spotting early corrosion signs lets you intervene before it becomes a full repipe situation.

Overview

What to Know

What Causes Pipe Corrosion

Low pH (acidic water) attacks copper and brass. High chlorine levels accelerate corrosion in all metals. High dissolved oxygen causes pitting in copper. Dissimilar metals in contact (copper connected directly to galvanized steel) create galvanic corrosion at the joint. Water velocity that's too high can cause erosion corrosion, especially at elbows.

Signs of Active Corrosion

Blue-green stains in sinks and tubs indicate copper corrosion. Rusty or brown water, especially in the morning after water sits overnight, suggests iron pipe corrosion. Pinhole leaks in copper pipes are a clear sign of pitting corrosion. White mineral buildup on galvanized fittings means the zinc coating is dissolving.

Testing Your Water

Home test kits ($15-$30) check pH, hardness, chlorine, and basic metals. For a comprehensive analysis, send a sample to a certified lab ($30-$50). Test both first-draw water (sits in pipes overnight -- shows pipe contribution) and flushed water (after running 2 minutes -- shows source water quality). The difference tells you what the pipes are adding.

Addressing Corrosive Water

Low pH: a calcite neutralizer filter raises pH naturally. High chlorine: a whole-house carbon filter removes it. Galvanic corrosion: install dielectric unions between dissimilar metals. For severe corrosion in galvanized pipes, repiping to copper or PEX is usually the long-term answer -- patching corroded galvanized is a losing game.

Pro Tips

Test your water annually if you're on a well. Municipal water is tested by the utility, but your pipes can still affect what comes out of the tap.
Blue-green stains don't mean your water is unsafe -- but they do mean your pipes are slowly being eaten away.
If you notice a metallic taste in your water, run the tap for 60 seconds before drinking. The metals concentrate in standing water.
When repiping, PEX is more resistant to corrosive water than copper and costs less to install.

Mistakes to Avoid

Ignoring blue-green stains -- they're a visible warning that copper corrosion is active.
Connecting copper directly to galvanized steel without a dielectric union. The galvanized pipe will corrode rapidly at the joint.
Assuming city water can't be corrosive. Municipal water can still have low pH or high chlorine.
Waiting for pinhole leaks before addressing corrosive water. By then, the pipes have been thinning for years.

When to Call a Pro

If you're getting pinhole leaks in copper pipes, multiple leaks in galvanized pipes, or consistently discolored water, have a plumber assess the system. They can camera-inspect the pipes and recommend targeted repairs or a full repipe.

Bottom Line

Test your water annually, watch for stains and discoloration, and address corrosive water chemistry before it eats through your pipes. A $30 water test can prevent a $10,000 repipe.