A trench is a narrow cut for something going underground: a water line to a new pool equipment pad, power to a detached shop, a sewer lateral, gas to an outdoor kitchen, or drip irrigation across a yard. The digging is quick. The planning around it, especially utility marking, is what keeps the job safe and legal.
Call Arizona 811 first
Arizona's underground facilities law applies to homeowners and contractors alike. Under A.R.S. 40-360.22, utilities have up to two working days to respond, and excavation can't begin until marking is complete or the excavator is told none is needed. Marks are valid for 15 working days. The Arizona Corporation Commission puts the fine for digging before lines are marked at up to $5,000 per violation. More on the Arizona 811 page.
How deep
HomeAdvisor's trenching guide gives these typical depths:
- About 24 inches for water supply lines
- About 36 inches for drainage pipes
- 12 to 24 inches deep and about 8 inches wide for general projects
What it costs
HomeAdvisor puts the average trenching job at $950, typically $400 to $1,200. Per linear foot:
| Dig | HomeAdvisor |
|---|---|
| Standard trenching | $5 to $12 per foot |
| Large or challenging digs | $13 to $40 per foot |
| 50 feet | $250 to $600 |
| 100 feet | $1,300 to $4,000 |
HomeAdvisor suggests a 15 to 20 percent contingency for problems like rock, and notes that rocky soil lengthens digging time. In caliche country that advice is worth taking.
Who should dig it
The Arizona Registrar of Contractors licenses excavation under R-2 (residential) and A-5 (commercial) classifications. Its A-12 and R-37R classifications cover excavating and backfilling for sewer, storm drain, water, gas and irrigation pipe, and R-21/C-21 covers trenching for irrigation systems. Ask which license the contractor holds for your job.
Sources
- Arizona Corporation Commission, Office of Pipeline Safety: Underground Facilities Law
- Arizona Revised Statutes 40-360.22: Excavations; determining location of underground facilities
- HomeAdvisor: How much does trenching cost? (updated June 19, 2026)
- Arizona Registrar of Contractors: License Classifications
Reviewed October 20, 2026. Rules, prices and contacts change, so check the source before relying on it.
Questions and answers
How much does trenching cost per foot?
HomeAdvisor's 2026 guide lists $5 to $12 per foot for standard trenching and $13 to $40 per foot for large or challenging digs.
Do I need to call 811 before trenching in my own yard?
Yes. The Arizona Corporation Commission says the call applies whether you're a homeowner or a contractor. It's free, and digging before lines are marked can bring fines of up to $5,000 per violation.
Get your trench quoted
Send the form or call and a local excavation contractor will follow up. There's no charge to ask for a quote.
If you reach voicemail, leave your name, number, the property address and what you need dug, graded or cleared.