Why Utility Location Can Change the Entire Project

Time to assemble this module into its big idea: on many lots, the utilities — not the view, not the yard — should choose where the ADU goes.

A tale of two placements

Same lot, same 750 SF ADU, two positions:

Plan A — the far back corner (it had the best afternoon light):

• 90-foot trenches for power and water, crossing a concrete patio: +$14K
• Sewer run too flat at that distance → ejector pump: +$6K (plus lifelong maintenance)
• Feeder run from a panel on the opposite side of the house: +$4K
• Patio demolition and restoration: +$8K
• Premium: ~$32K–$38K — before anything about the building itself changed.

Plan B — shifted 35 feet toward the house's utility side:

• Short trenches through soft yard, gravity sewer, short feeder. Premium: ~$0.

The afternoon light was nice. Was it $35,000 nice? That's a real question with no wrong answer — but it should be asked, and most homeowners never get the chance because nobody mapped the utilities before the design was drawn.

The checklist that finds your cheap spot

Before placement is chosen, someone should locate: the sewer lateral's path and depth; the electrical panel's location and capacity; the water service's route; the gas line (if using); overhead lines and their clearances (Module 2); and anything expensive to cross — concrete, mature trees, retaining walls. Overlay those on the setback map from Module 2 and the lot will practically point at its own best spot.

When the expensive spot wins anyway

Sometimes the far corner truly is right — privacy, views, or preserving the yard's best space between the homes. Fine! Spending $30K deliberately on placement value is a legitimate choice. Spending it accidentally is the thing this module exists to prevent.