Cost GuideUpdated June 11, 2026
Adding a second bathroom is one of the most practical upgrades you can make in a Round Lake home. With families growing and schedules getting tighter, one bathroom often means morning traffic jams and extra stress. In our experience, the biggest challenges are almost always under the surface, hidden in walls, floors, and the plumbing system itself.
Where to Put the New Bathroom
Most homes built in Round Lake since the 1990s have modern plumbing layouts, which makes adding another bathroom much easier compared to older homes. Common spots for a second bath include finishing the basement, splitting a large upstairs room, or converting part of a walk-in closet. We see plenty of homeowners ask about basement bathrooms, but the heavy clay soil and high water table in this area can complicate proper drainage, so planning is key.
Key Considerations for Plumbing Connections
Before any walls go up, you need a solid plan for water supply, drain, and vent lines. In newer homes, copper or PEX supply lines and PVC drains are common, but some long-held family homes around Round Lake still rely on older galvanized or cast iron pipes. These pipes may need upgrades or replacement to handle additional fixtures. Connecting to the main waste line often means opening up the floor, especially in basements. Heavy clay soil outside complicates digging, and outdated clay-tile sewer lines can be brittle or obstructed by roots. Our sewer line services have uncovered plenty of local issues like these.
Understanding the Costs
The cost to add a second bathroom can swing a lot based on location, size, and plumbing complexity. On average, adding a small half-bath near existing plumbing runs less than building a full bath in a basement far from the main stack. Factor in demo, framing, fixtures, electrical, and flooring alongside plumbing labor and materials. You also need to budget for permits and inspections, which Lake County requires for bathroom additions. Delays can hit if the plumbing layout isn't up to code.
Common Plumbing Steps in a Bathroom Addition
- Assess main supply and drain lines for capacity and material
- Plan fixture locations with proper slope for drainage
- Rough in water, drain, and vent pipes before walls are finished
- Install shutoff valves for each new fixture
- Test all connections for leaks before moving forward
- Set and seal the toilet, vanity, and shower or tub after floor installs
If your water heater is already near its limit, adding another bath could mean an upgrade. We offer water heater services to help size and swap out units so you don't end up with a cold shower as soon as the new bathroom is finished.
Drainage, Sump Pumps, and Preventing Basement Backups
Because Round Lake sits on heavy clay with a high water table, basement bathrooms need special attention. If your new bath sits below the main sewer line, you'll likely need an upflush system or an ejector pump to move waste and water upward. It's also wise to check the condition of your sump pit and pump before pouring any new concrete. You don't want a failed sump pump causing water to back up into a newly finished space. Our sump pump services can help make sure your system is up to the job.
Slow drains or backups can indicate an underlying issue with your main line or vent stack. If you're noticing gurgling sounds or frequent clogs, consider a professional drain cleaning before construction starts.
Permits, Inspections, and Doing It Right
Lake County and the Village of Round Lake both require permits and inspections for adding a bathroom. Your plans will need to show plumbing layout, venting, fixture placement, and drainage details. Inspections check for proper slope, venting, backflow prevention, and that all work follows local building codes. Cutting corners here leads to costly re-work down the line.
Older homes, in particular, can reveal hidden pipe or drainage problems during a remodel. We help with pipe repair and repiping so your new bath won't overload old lines or cause leaks in places you can't see.
Choosing Fixtures and Getting a Reliable Install
The right fixtures make all the difference in both daily use and long-term maintenance. Water-saving toilets, pressure-balanced shower valves, and easy-access shutoffs are all good choices. Proper installation of every faucet and fixture is crucial to prevent future leaks or damage. Our team handles faucet and fixture installation so your new bath works smoothly from the start.
If you're ready to add a second bathroom or want a ballpark idea of what's involved, our team is ready to help. Call us at 224-308-1299 for honest answers, estimates, and a straightforward approach to plumbing upgrades in Round Lake homes.