Cathodic Protection Testing in Corpus Christi, TX
Subtropical Gulf Coast climate.
For cathodic protection testing, the service area covers roughly 40 miles from central Corpus Christi.
Common reasons to call
- A buried pipeline, well casing, or storage tank needs its yearly corrosion-control check
- A rectifier or impressed-current system stopped working or is reading wrong
- An operator has to prove the system is working for a pipeline compliance survey
- New coated steel or a new tank was put in the ground and the crew wants a baseline reading
- Old anodes on a water tank or boat dock may be used up and need checking
- Readings drifted out of the safe range and someone needs to find out why
- A company is buying or leasing a facility and wants the corrosion protection checked first
- Nearby digging, welding, or a new power line may be causing stray-current corrosion
Typical work
- Yearly pipe-to-soil potential survey on a buried steel line
- Rectifier check and tune-up for an impressed-current system
- Anode inspection and reading on a water storage tank or marine structure
- Close-interval survey to map protection levels foot by foot along a pipeline
- Baseline testing on a newly installed and coated steel system
- Stray-current investigation near power lines, rail, or other pipelines
- Test-station reading and record-keeping for a compliance file
Typical turnaround
A small tank or single-point check is often done in a day. A full survey with a written report usually lands within a week. Close-interval surveys and stray-current studies on long lines can take one to several weeks depending on distance and access.
Materials and equipment
- Digital multimeter and voltmeter rated for field use
- Copper-copper sulfate reference electrode (half cell)
- Test leads, clips, and reels of wire
- Rectifier and DC power components
- Sacrificial anodes (magnesium, zinc, or aluminum) when replacement is needed
- Impressed-current anodes and cabling
- Data logger or GPS unit for close-interval surveys
- Test stations and junction boxes
Job sizes
Minor
A single test station or one tank read, with a short written record of the numbers.
Standard
A full pipe-to-soil survey across several test points, a rectifier check, and a written report for the file.
Major
A close-interval survey along a long run of pipeline, or a stray-current investigation that takes several days and detailed mapping.
Replacement
Designing and installing a new cathodic protection system, or replacing spent anodes and a failed rectifier, then testing to confirm it holds.
Final pricing comes from the on-call provider after on-site assessment, with a written estimate before any work starts.
What to expect
- ✓A good pro takes readings with a calibrated meter and a copper-copper sulfate reference electrode, not just the rectifier dial.
- ✓They give you written records with the actual numbers, the date, and the test locations, so you have a file to compare against next year.
- ✓They hold current AMPP (formerly NACE) cathodic protection certification and can show it.
- ✓For regulated pipelines they meet operator qualification rules and understand Railroad Commission and federal monitoring requirements.
- ✓They explain what your readings mean in plain language and only recommend fixes the data actually supports.
- ✓They check for stray-current issues from nearby power, rail, or other buried systems, not just your own equipment.
- ✓They carry general liability insurance and can provide proof on request.
- ✓They set up or confirm a testing schedule that matches your system and any rules that apply to you.
Look for a technician certified through AMPP (formerly NACE), such as a CP Tester, CP Technician, or CP Specialist. Good pros also carry general liability insurance, and for pipeline work they meet operator qualification (OQ) requirements. Ask to see current certification cards and proof of insurance.
Common questions
What is cathodic protection testing?
It is a way to check that buried or underwater steel is being protected from rust. Steel in soil or water slowly corrodes. Cathodic protection sends a small electric current to the metal to stop that. Testing measures the voltage between the steel and the ground to make sure the protection is strong enough.
How often should it be tested?
For regulated pipelines, federal and Railroad Commission rules generally call for monitoring at set times each year, and rectifiers are checked more often than that. Tanks, docks, and non-regulated systems are commonly checked once a year too. Ask your pro what schedule fits your system and any rules that apply to you.
What does a good reading look like?
The most common target people talk about is a pipe-to-soil potential around negative 0.85 volts using a copper-copper sulfate reference. That is a general guideline, not a promise for every case. A qualified tester will explain what your specific readings mean and whether any correction is needed.
Do I really need a certified technician?
For steel that matters, yes. The readings are easy to take wrong, and a bad reading can hide real corrosion or trigger repairs you did not need. Look for someone certified through AMPP (the group that used to be called NACE). For regulated pipelines, the person also needs to meet operator qualification rules.
What is the difference between sacrificial anode and impressed current?
A sacrificial anode is a chunk of metal like magnesium or zinc that slowly wears away to protect your steel, with no power hookup. An impressed-current system uses a rectifier plugged into electricity to push a stronger, adjustable current. Big pipelines and large tanks often use impressed current. Testing checks either kind.
My rectifier shows a number, isn't that enough?
Not by itself. The rectifier dial tells you it is putting out current, but it does not tell you the steel is actually protected along its whole length. A tester takes readings at points in the ground to confirm the protection is reaching the metal everywhere it should.
What is a close-interval survey?
It is a detailed walk along a pipeline where readings are taken every few feet instead of only at test stations. It builds a picture of protection over the whole line and helps find weak spots, coating damage, or stray-current problems that spot checks would miss.
What is stray current and why does it matter?
Stray current is electricity leaking through the ground from another source, like a power line, rail system, or a neighbor's protection system. It can speed up corrosion on your steel even if your own system looks fine. A tester can spot the signs and help figure out where it is coming from.