Get an INSTANT estimate of the cost to Install a Lawn Irrigation System! Our free calculator uses recent, trusted data to estimate costs for your Lawn Irrigation System Installation project.For a basic 500 square feet project in zip code 47474, the benchmark cost to Install a Lawn Irrigation System ranges between $1.40 - $2.21 per square foot* . To estimate costs for your project: 1. General contractor overhead and markup for organizing and supervising the Lawn Irrigation System Installation. 2  Add 15% to 23% to the total cost above if a general contractor will supervise this project. 3  Sales tax on materials and supplies.