Union County, New Jersey · For builders and owners

What can you build in Mountainside?

The single-family zoning rules in Mountainside, zone by zone, read from the town ordinance by our builder desk. Then check any address to see what fits on that lot.

Single-Family Zones

Mountainside zoning, zone by zone.

Zone	Min lot (sq ft)	Min width	Front	Side (each / total)	Rear	Bldg coverage	Height	FAR
R-1 R-1 Single Family Residence District	20,000	110 ft	30 ft	10 ft	30 ft
R-2 R-2 Single Family Residence District	15,000	100 ft	30 ft	10 ft	30 ft	15%	35 ft	0.225

Source: Borough of Mountainside Land Use Ordinance (Sections 1008 R-1, 1009 R-2, 1010 R-3 Single Family Residence Districts); Borough Building/Zoning/Engineering web page zoning requirement summary (R-1, R-2). Read 2026-09-28. Only zones we could confirm from the ordinance are shown. Rules change and have exceptions (corner lots, undersized lots, steep slopes, overlays), so confirm with the town zoning officer before you buy or design.

What Builders Build Here

What the market pays for new homes in Mountainside.

Zoning tells you what you are allowed to build. These numbers tell you what sells.

14teardowns since 2019older homes and lots bought by builders

$519Kmedian builder paidfor the old house and lot

3,710median new home, sq ftnew homes sold, last 2 years

$1.71Mmedian new home price3 sold, last 2 years

Check A Lot

Check any Mountainside address.

Enter an address and we will show the lot size, its zone, roughly how big a new home could be, and how likely a builder is to want it.

Check a lot in MountainsideFree, instant, from the state parcel map and this ordinance.Get our full read on a parcelZoning, density, subdivision, what it will sell for and how fast.Builder deal sheetMonthly: teardown and land opportunities in the towns you build in.

Tonye Ikiere

Written and reviewed by

Tonye Ikiere

REALTOR-Associate, Builders Resource Center at Corcoran Sawyer Smith. Advises builders and owners in Mountainside. Numbers updated September 2026.

About Tonye · (732) 913-9250

Keep Exploring

More on Mountainside.

Selling a home in MountainsideWhat homes sold for, what a builder might pay, and a free price estimate.Moving to MountainsideWhat your budget buys, how old the homes are, and what is for sale now.

Mountainside market reportEvery home sold, median prices and the agent who knows the town.Land and teardowns in MountainsideWhat builders paid for older homes, and lots for sale now.What can you build on your lot?Enter an address: zoning, lot size and roughly how big a new home could be.