Running out of space but need both a dishwasher and a washing machine? You’re not alone. Many US homeowners—especially in apartments or compact homes—want to install a dishwasher right next to their washing machine to maximize utility space. But how to plumb in a dishwasher next to washing machine without leaks, code violations, or costly mistakes? This guide walks you through the entire process with clarity, safety, and confidence—even if you’ve never held a wrench before.
Can You Install a Dishwasher Next to a Washing Machine?
Yes—absolutely. In fact, it’s a common setup in modern US homes, especially where kitchens and laundry rooms share a wall or are combined (like in many condos or townhomes). Both appliances require water supply and drainage, and when properly installed, they can share plumbing infrastructure efficiently.
However, there are critical considerations:
Local plumbing codes (which vary by state)
Water pressure and flow requirements
Drain line separation to prevent backflow
Electrical safety (GFCI outlets required per NEC)
According to the International Residential Code (IRC), dishwashers and washing machines can share a drain stack only if each has its own P-trap and air gap or high-loop configuration. Never connect them directly to the same drain pipe without proper separation.
💡 Pro Tip: Always check with your local building department. In California, for example, dishwashers must have an air gap device; in Texas, a high loop may suffice.
GFCI outlet (or confirm existing one is compliant), voltage tester
⚠️ Safety First: Turn off water at the main shutoff and electricity at the breaker before starting.
Step-by-Step Guide: How to Plumb In a Dishwasher Next to Washing Machine
Step 1: Confirm Shared Wall Access & Space
Measure the area. Most standard dishwashers are 24″ wide, while washing machines range from 24″–27″. Ensure at least 1″ clearance on each side for airflow and vibration control.
Check behind the wall (if possible) to locate:
Hot and cold water lines
Drain stack location
Electrical outlet position
If both appliances will sit side by side, aim to align their rear panels within 6″ of each other for easier plumbing.
Step 2: Install Dual Shutoff Valves
Instead of using separate valves for each appliance, install a dual-angle stop valve (also called a “laundry box” or “appliance manifold”) on the cold water line. This provides two independent shutoffs in one compact unit.
Mount it 36–42″ above the floor (standard height).
Use Teflon tape on all threaded connections.
Connect one outlet to the washing machine’s cold inlet, the other to the dishwasher’s hot water inlet (yes—dishwashers use hot water, usually sourced from the hot line, but some models can use cold).
📌 Note: Most dishwashers heat their own water, so connecting to the hot water line improves efficiency and cleaning performance. Confirm your model’s manual.
Step 3: Set Up Drain Connections Separately
Never share a direct drain hose. Each appliance must have its own path to the drain stack.
Washing Machine: Uses a 2″ standpipe with a P-trap, vented to code.
Dishwasher: Requires either:
An air gap (mounted on the countertop or sink deck), or
A high loop (drain hose secured at least 20″ above the floor under the sink)
If installing next to a washer, route the dishwasher drain hose up to the underside of the countertop, then down into the garbage disposal or dedicated drain branch.
Place the dishwasher and washing machine in position. Use a level to ensure they’re even—uneven appliances vibrate excessively and can damage hoses.
Adjust the front feet as needed.
Leave 4–6″ of clearance behind for hose access.
Secure anti-tip brackets if required (common for dishwashers).
Step 5: Connect Supply Lines & Test for Leaks
Attach braided stainless supply lines to each appliance.
Hand-tighten, then give a quarter-turn with a wrench—do not overtighten.
Slowly turn on water valves.
Place towels underneath and run both appliances on a short cycle.
Check every connection for drips over 10 minutes.
If you spot a leak, shut off water immediately and re-tape or re-tighten.
Common Mistakes to Avoid
Mistake
Why It’s Bad
Fix
Sharing a single drain hose
Causes backflow of dirty water into dishwasher
Use separate drains with air gap/high loop
Using old rubber hoses
Prone to bursting (causes flooding)
Replace with stainless braided hoses
Ignoring GFCI requirement
Risk of electrocution near water
Install GFCI outlet within 6 ft
Skipping the shutoff valve
Hard to service appliances
Always install dual shutoffs
According to the Insurance Institute for Business & Home Safety (IBHS), over 50% of home water damage claims stem from appliance hose failures—most preventable with proper installation.
Pros and Cons of This Setup
✅ Pros
Saves valuable floor space
Reduces plumbing runs (lower cost)
Easier maintenance access (both in one zone)
Ideal for open-concept or small homes
❌ Cons
Noise from both machines running simultaneously
Requires careful planning to meet code
Potential for moisture buildup if ventilation is poor
💬 Real-World Example: Sarah from Portland, OR, installed her Bosch dishwasher next to her LG washer in a 6′ utility closet. By using a dual shutoff valve and routing the dishwasher drain to the sink’s garbage disposal, she passed inspection on the first try—and saved $400 vs. hiring a plumber.
A: It depends on your municipality. In most US cities, minor appliance replacements don’t require permits, but new plumbing lines or electrical work might. When in doubt, call your local building department—it’s free and prevents fines later.
Q2: Can both appliances use the same electrical outlet?
A: No. The National Electrical Code (NEC) requires each major appliance to have its own dedicated circuit. Dishwashers typically need a 120V/15A or 20A circuit, and washing machines often require 120V/20A. Sharing an outlet risks tripping breakers or overheating.
Q3: What if there’s no hot water line near the washer?
A: You can run a hot water line from the nearest source (e.g., under the sink), or connect the dishwasher to the cold line—many modern models compensate by heating water internally. However, using hot water improves drying and cleaning, so it’s recommended if feasible.
Q4: How far can the dishwasher be from the sink drain?
A: Ideally, within 10 feet. Longer runs increase the risk of clogs and slow drainage. If you must go farther, use a larger diameter hose (⅝”) and ensure a consistent downward slope (¼” per foot).
Q5: Is it safe to stack a dishwasher on top of a washing machine?
A: Never. Dishwashers are not designed for vertical stacking. The weight, vibration, and water exposure create serious safety hazards. Always install both units on the floor.
Q6: How often should I replace supply hoses?
A: Every 5 years, or immediately if you see bulges, cracks, or corrosion. Stainless steel braided hoses last longer than rubber but still degrade over time.
Conclusion
Learning how to plumb in a dishwasher next to washing machine isn’t just about saving space—it’s about smart, code-compliant home improvement that boosts convenience and value. With the right tools, a bit of patience, and attention to detail, you can complete this project safely over a weekend.
Not only will you avoid costly plumber fees (average US installation: $180–$350), but you’ll also gain confidence in handling future DIY upgrades.
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