5 Common Mistakes to Avoid When Planning Your ADU in Ithaca

An ADU is a major project, and a handful of avoidable mistakes account for most of the delays and budget overruns we see. Here are five to watch for.

First, skipping the zoning check. Confirm your property's zone and the applicable size, setback, and parking rules before investing in design. Building plans that don't fit your zone wastes time and money.

Second, underestimating the budget. Account for design, permitting, utilities, and finishes — not just construction. A contingency of 10–15% protects against surprises.

Third, ignoring utility capacity. Water, sewer, and electrical connections must be verified early; upgrades can be costly and affect feasibility.

Fourth, over-customizing the design beyond what the lot or budget supports. And fifth, choosing a contractor without ADU experience. The permitting and code nuances of accessory units reward specialists who've done it before.