Guides
Everything you need to know about ADUs
Short answers first, details after, sources on every page. Written for homeowners, not lawyers.
Start with what you’d use it for
Start with the person, not the building. Who it’s for decides the kind of ADU that fits, the town rules that matter most and what it means for your money.
A parent or aging relative
One-level living and room for family nearby. Local rules determine whether a separate home or an apartment connected to your house is possible.
What it means for you →An adult child
Their own front door and kitchen. Compare a conversion, an addition, or a separate home against local rules and the property.
What it means for you →Rental income
Check whether rental use is allowed, then weigh build costs and ongoing expenses against realistic rent.
What it means for you →Downsizing on your own land
Move into a smaller one-level home and keep the property. Read your town’s owner rule closely.
What it means for you →Office, studio or guests
Different rules can apply to storage, office work, and overnight stays. Tell your town how you’ll use the space before planning.
What it means for you →Short stays and vacation rentals
Many towns limit stays under 30 days or require a permit. Check before you plan around it.
What it means for you →Basics
What an ADU is and the kinds you can build.
What is an ADU?
An ADU is a small second home on the same lot as a house. The main kinds, why people build them, how they differ from look-alikes, and who decides.
Read the guide →What will you use an ADU for?
Start with who will use your ADU: a parent, an adult child, a tenant, short-term guests, you or a home office. See the type, rules and money questions for each.
Read the guide →ADU types: which kind fits your home?
Basement and attic conversions, attached additions, backyard cottages, garage units and junior ADUs compared on size, cost, approvals, pros and cons.
Read the guide →Rules
Who decides, how approval works and how to check your town.
How do ADU permits work, from idea to move-in?
The ADU permit path in plain English: checking it's allowed, zoning approval, the building permit, inspections and move-in, with New York timelines.
Read the guide →How do you check your town's ADU rules?
Find out if your town, village or city allows an ADU: who governs your lot, your zoning district, how to read the code, and how to get the answer in writing.
Read the guide →Money
What it really costs and how people pay for it.
What does an ADU cost?
Published ADU cost ranges by type, the line items in a finished project, what raises costs on Finger Lakes lots, and how to read a builder or prefab quote.
Read the guide →How do people pay for an ADU?
How homeowners pay for an ADU: cash, HELOCs, home equity loans, refinancing, construction and renovation loans, ADU rent rules and New York's Plus One grant.
Read the guide →Building
Site, utilities, construction types and building for winter.
How are ADUs built? Site-built, modular and more
Site-built, panelized, modular, HUD manufactured and kit ADUs compared: timelines, design freedom, who inspects the work and what to ask a supplier.
Read the guide →Can your lot take an ADU? Site, utilities and foundations
Setbacks, slope, crane access, flood zones, wetlands, sewer or septic, wells, power and frost-proof foundations: what to check before you pay for plans.
Read the guide →How do you build an ADU for Finger Lakes winters?
Snow loads and roof pitch, frost-proof foundations, New York's 2025 energy code, cold-climate heat pumps, freeze-safe pipes, ice dams and what to ask a builder.
Read the guide →Can a tiny house or park model be an ADU?
Why tiny houses on wheels and park-model RVs usually aren't legal year-round homes, when a tiny house on a foundation can be, and how to ask your town.
Read the guide →Living with an ADU
Renting, taxes, insurance and building for family.
Renting an ADU, taxes and insurance
Can you rent an ADU near Rochester, and will rent cover it? Owner rules, local rents, a loan example, landlord duties, short-term rentals, taxes and insurance.
Read the guide →How do you build an ADU for aging in place?
Planning an ADU for a parent or for your own later years: zero-step design, one-level layouts, privacy, family-only town rules and money questions.
Read the guide →Room for what comes next
Your next chapter could be closer than you think.
Start with what’s possible. Find the rules, explore the options, and take it one question at a time.