811 vs Professional Utility Locating in Hawaii: What's the Difference?
Before you dig anywhere in Hawaii, you've probably heard "call 811." It's the law, and it's good advice — but 811 alone doesn't protect you from the most common utility strikes on Maui. Here's what 811 actually covers, and what it doesn't.
What Is 811?
811 is Hawaii's one-call notification system. When you call or submit online, it notifies registered public utilities — Hawaiian Electric, the water department, telecom providers — to come mark their lines on your property. It's free, legally required before excavation, and takes 2 business days minimum.
It is an essential first step. But it is only a first step.
What 811 Does Not Cover
This is where most Maui property owners are surprised. 811 only locates publicly owned utilities up to the meter or service connection. Everything beyond that point is your responsibility.
| What You Need to Find | 811 Covers It? | Professional Locate Needed? |
|---|---|---|
| Public power lines to your meter | ✓ Yes | ◑ Optional |
| Public water main to your meter | ✓ Yes | ◑ Optional |
| Private water lines on your property | ✗ No | ✓ Yes |
| Irrigation / agricultural lines | ✗ No | ✓ Yes |
| Cesspools and septic systems | ✗ No | ✓ Yes |
| Private sewer laterals | ✗ No | ✓ Yes |
| Depth of any utility | ✗ No | ✓ Yes |
| Non-metallic / PVC pipe | ✗ No | ✓ Yes |
| Undocumented or unknown lines | ✗ No | ✓ Yes |
The Gap That Causes Most Strikes
According to national damage prevention data, approximately 65% of all buried utilities are privately owned and not covered by one-call systems like 811. On Maui, this percentage is often higher due to the prevalence of older, undocumented infrastructure on residential and agricultural properties.
Real Scenarios Where 811 Isn't Enough on Maui
Scenario 1 — Excavating near an older home
You're installing a new fence post line on a Kula property built in the 1960s. 811 marks the power line from the street. Your excavator hits a private irrigation line that feeds the entire upper field — no records, no markings, no warning. Cost: pump replacement, repairs, lost irrigation for the season.
Scenario 2 — Real estate transaction with a cesspool
A Maui Realtor's buyer is purchasing a property in Haiku. 811 completes their markings. Nobody locates the cesspool. Two months after closing, the new owner's contractor punctures the cesspool lid during grading. The cesspool wasn't disclosed because nobody knew where it was.
Scenario 3 — Tree removal near a structure
A tree service on a Wailuku residential lot calls 811 before grinding stumps. The public lines are marked. An unmarked private water service line runs along the tree root zone. The grinder severs it. Emergency plumber call on a Saturday: $1,200 before parts.
How Professional Locating Complements 811
Professional locating using GPR and EM technology extends the protection that 811 starts. Where 811 marks the public infrastructure, a professional locate identifies private lines, unknown infrastructure, cesspools, tanks, and non-metallic features that 811 simply cannot see.
Together, they give you the most complete picture of what's below before you break ground.
IMI Systems Recommendation
Always call 811 first — it's the law and a smart starting point. Then contact IMI Systems to locate the private infrastructure 811 doesn't cover. For most Maui excavation projects, the cost of a professional locate is a fraction of a single utility strike or emergency repair.
Frequently Asked Questions
Is calling 811 enough before I dig on my Maui property?
811 is legally required and a necessary first step — but it only covers publicly owned utilities to your meter. Private lines, cesspools, irrigation systems, and undocumented infrastructure require a professional locate with GPR and EM equipment.
How long after calling 811 can I dig?
Hawaii law requires a minimum of 2 business days after notifying 811 before excavation. Markings are typically valid for 15 days. Check current Hawaii one-call requirements for your specific project.
Who is liable if I hit an unmarked private utility?
Generally, the excavator is responsible for private utilities on a property. This is a strong reason to invest in professional private utility locating before any dig — it shifts the burden of due diligence onto documented, professional findings.
Already called 811 — now cover what it misses.
IMI Systems locates the private utilities, cesspools, and undocumented infrastructure that 811 doesn't see. Serving all of Maui.Schedule a Locate →