Install Fixtures and Appliances
This is where your ADU comes together. Installing fixtures and appliances is exciting because you can finally see the finished product taking shape. Take your time, test everything thoroughly, and do not rush - small leaks or improper connections now become big problems later.
Quick Summary
Timeline
2-4 days
Key focus
Test everything
Inspection
Final plumbing check
Why Proper Installation and Testing Matters
Fixtures and appliances are what your tenant will interact with every day. Poor installation leads to leaks, malfunctions, and frustrated tenants. Thorough testing before move-in catches issues while your contractor is still on-site. Key goals:
- Leak-free connections at every water supply and drain
- Proper hot water delivery to all fixtures (verify temperature)
- All appliances functioning correctly through full cycles
- Documentation of warranties and manuals for all equipment
Kitchen Fixture Installation
Install Kitchen Sink and Faucet
The kitchen sink sees heavy daily use. Ensure tight connections and proper drain assembly to prevent leaks under the cabinet.
- • Drop-in sinks are easier to install; undermount requires countertop support
- • Connect supply lines with braided stainless steel (not plastic)
- • Install basket strainer with plumber's putty or silicone
- • Connect P-trap and ensure proper slope to wall drain
- • Install garbage disposal if included (dedicated circuit required)
- • Test hot and cold water flow and check all connections for leaks
Install Dishwasher
Dishwashers require water supply, drain connection, and dedicated electrical circuit. Proper installation prevents leaks and ensures code compliance.
- • Connect water supply via dishwasher elbow under sink (most common)
- • Install high loop or air gap in drain line (code requirement)
- • Hardwire or plug to dedicated 15/20 amp circuit
- • Level the dishwasher using adjustable feet
- • Secure to countertop with mounting brackets
- • Run full cycle and check for leaks during and after
Pro tip: Run the dishwasher empty on a full cycle before leaving the job site. Stay and watch for leaks at supply, drain, and door seal.
Install Range or Cooktop
Whether gas or electric, proper installation and ventilation are essential for safety and performance.
- • Gas range: Connect with flexible gas connector, test for leaks with soap solution
- • Electric range: Requires dedicated 240V circuit (40-50 amp)
- • Induction cooktop: Needs 240V circuit, verify cookware compatibility
- • Install anti-tip bracket for freestanding ranges (code requirement)
- • Ensure proper ventilation - range hood or microwave with exhaust
- • Test all burners and oven (if applicable) for proper operation
Install Refrigerator
Refrigerators are relatively simple to install but need proper clearance and water connection if equipped with ice maker.
- • Verify opening dimensions match refrigerator size
- • Allow 1-2 inches clearance on sides and top for ventilation
- • If ice maker: install water supply line with saddle valve or dedicated shutoff
- • Level the refrigerator (slightly higher in front helps door close)
- • Clean inside and remove all shipping materials
- • Allow 24 hours to reach temperature before stocking with food
Bathroom Fixture Installation
Install Shower Valve and Head
The shower valve was roughed in during plumbing - now install the trim kit, handle, and showerhead. Test water temperature and pressure.
- • Install valve trim plate and handle per manufacturer instructions
- • Attach shower arm and head (use thread tape on connections)
- • If tub/shower combo, install tub spout and diverter
- • Set anti-scald limit stop to prevent water over 120 degrees F
- • Test both hot and cold, verify smooth temperature adjustment
- • Check for leaks at valve, arm, and drain during operation
Set and Connect Toilet
Toilet installation is straightforward but must be leak-free. A leaking toilet wax ring can cause major water damage.
- • Install new wax ring on flange (or use wax-free seal like Fluidmaster)
- • Set toilet bowl onto bolts, press down firmly to compress seal
- • Tighten closet bolts alternately, do not over-tighten (cracks porcelain)
- • Install tank (if two-piece), connect supply line
- • Flush multiple times and check for leaks at base and supply
- • Apply small bead of caulk around base (leave back open for leak detection)
Note: If the toilet rocks, use plastic toilet shims before caulking. A rocking toilet will eventually break the wax seal and leak.
Install Vanity Faucet and Drain
Complete the vanity installation by connecting the faucet, drain, and P-trap. This is often the last plumbing connection.
- • Mount faucet to sink per manufacturer instructions
- • Connect supply lines (hot on left, cold on right when facing sink)
- • Install pop-up drain assembly with plumber's putty or silicone
- • Connect P-trap to drain tailpiece and wall stub-out
- • Test both hot and cold, check all connections for leaks
- • Verify stopper operates correctly
Test Exhaust Fan
Verify the bathroom exhaust fan is properly connected and functioning. Proper ventilation prevents mold and moisture damage.
- • Turn on fan and verify it runs quietly and smoothly
- • Check that damper opens and closes properly
- • Hold tissue paper to grille - it should be drawn in
- • Verify exterior vent opens when fan runs and closes when off
- • If humidity sensing, test automatic operation
- • Note: fan should run for 20 minutes after showers to clear moisture
Complete Testing Checklist
Before considering fixtures complete, verify every item on this list:
Common Installation Mistakes
Not Testing Under Pressure
Connections that seem tight can leak under water pressure. Run water at full pressure for several minutes and check every connection with a dry paper towel.
Forgetting Anti-Scald Settings
Shower valves have adjustable limit stops to prevent scalding. Set these to limit maximum temperature to 120 degrees F, especially important for families or elderly.
Losing Manuals and Warranties
Collect all product manuals, warranty cards, and receipts. Create a folder for the tenant/property file. Warranties are void without proof of purchase.
Over-Tightening Connections
Plastic fittings and porcelain fixtures crack if over-tightened. Hand-tight plus a quarter turn is usually sufficient for most supply line connections.
Frequently Asked Questions
How long should I run water to test for leaks?
Run each fixture for at least 5 minutes while checking connections. For the dishwasher, run a complete cycle. Some leaks only appear when connections warm up or when full pressure is applied, so extended testing catches more issues.
Do I need an inspection after fixture installation?
Yes, final plumbing and electrical inspections are required before the Certificate of Occupancy is issued. The inspector will verify proper connections, test GFCI outlets, check water heater settings, and ensure code compliance.
Should I use thread tape or pipe dope?
Use PTFE thread tape (Teflon tape) on threaded water supply connections. Wrap 3-5 times in the direction of the threads. Pipe dope works too but is messier. Do not use tape on compression fittings - the compression seal does the work.
What if hot water takes too long to reach the fixture?
Long hot water wait times are common in ADUs due to distance from the water heater. Solutions include: dedicated tankless water heater for ADU, point-of-use water heater under the sink, or a recirculating pump system. Expect 30-60 seconds wait time in typical setups.
Ready for the Next Step?
With fixtures installed and tested, the final Kitchen/Bath step is adding all the finishing details - hardware, towel bars, and light fixtures that complete the space.