FREQUENTLY ASKED QUESTIONS

Frequently Asked Questions

  • Many residential projects require a licensed civil engineer, including cesspool conversions, grading permits, drainage plans, stormwater management, retaining walls, and site improvements. If your project involves changing the land, managing runoff, or obtaining County approvals, a civil engineer can prepare the required plans and help guide you through the permitting process.

  • Grading that exceeds 100 CY or 4 vertical ft requires a permit. If you’re in the Special Management Area, then grading exceeding 50 CY and 2 vertical feet requires a permit. Most building permits require a corresponding grading permit. Green Trees Engineering can evaluate your project, determine permit requirements, and prepare the necessary grading and drainage plans.

  • Engineering fees vary based on the project scope, site conditions, and permitting requirements. Typical engineering fees include:

    • Cesspool Conversion / IWS Design: $2,500–$4,500

    • Minor Grading Permits (under 1 acre): $8,000–$12,000

    • Major Grading & Drainage Projects (over 1 acre): Starting around $30,000

    • Sewer Laterals, Water Meter Relocations, Driveway Permits, SMA permits, etc.: $5,000–$20,000

    • Commercial, Municipal, and large scale residential subdivision jobs are more expensive; please reach out for a individualized proposal.

    Every project is unique, and we'll provide a clear, detailed proposal before any work begins.

  • Project timelines vary depending on the complexity of the design and agency review times. Simple residential projects may be completed in a matter of weeks, while projects requiring additional studies or multiple agency approvals can take longer. Our existing relationships with regulatory agencies, combined with our experience designing similar projects in Maui County, allow us to efficiently move your permit through the process.

  • Residents in Hawaii need to convert their cesspool by 2050 in order to comply with Hawaii laws. A cesspool conversion replaces a cesspool with a modern wastewater treatment system that meets current State of Hawaii requirements. The process typically includes a site evaluation, engineering design, County permitting, construction, and final approval. We work closely with homeowners, contractors, and permitting agencies to make the process as straightforward as possible.

  • Absolutely! You don't need to know exactly what permits, plans, or engineering services your project requires before reaching out. Tell us a little about your property and what you're hoping to do, and we can help you determine the appropriate next steps.

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