Before you sign off on a floor plan for a commercial renovation, settle four plumbing questions. Can the existing drains, water service, and water heater handle what the new tenant will do there? Will the work trigger accessible restroom upgrades? Does the business need a grease interceptor or backflow preventer? And which permits and inspections will Catawba County require? Those answers shape your budget and timeline more than almost any finish choice, and they are much easier to deal with on paper than after the drywall goes up. This guide walks through each one, using code requirements and guidance from federal and state agencies, so you can have a more productive conversation with your architect, general contractor, and plumber in Conover, NC.
Start With How the Space Will Be Used
The single biggest plumbing driver in a renovation is the change in use. A former retail store becoming a café, a warehouse becoming offices, or an office becoming a medical practice can each change what the plumbing system has to do.
North Carolina’s plumbing code sets minimum fixture counts (toilets, sinks, drinking fountains, service sinks) based on the building’s occupancy type and the number of people expected to use it. When the use changes, the required count can change too. A space that had one restroom as a small shop may need more fixtures, or separate restrooms, once it becomes a gathering space where more people are present at once.
Use also changes the load on drain lines and the water heater. A dental office needs sinks in treatment rooms. A salon needs shampoo bowls with steady hot water. A restaurant adds floor drains, prep sinks, and dishwashing. Each one adds demand that the original system may not have been sized for.
Here is how common use changes tend to affect plumbing scope:
| Change of Use | Plumbing Items Commonly Affected | Questions to Ask Early |
| Retail to restaurant or café | Grease interceptor, floor drains, hand sinks, prep sinks, larger water heater, gas lines for cooking equipment | Does the sewer provider require a grease control permit? Where can an interceptor physically go? |
| Warehouse to office | More restrooms, new drain runs under slab, break room sink, drinking fountain | How far are new fixtures from the existing drain line? Will the slab need to be cut? |
| Office to medical or dental | Sinks in exam or treatment rooms, specialty equipment connections, backflow protection | Does any equipment connect to the water supply in a way that needs backflow protection? |
| Retail to salon or spa | Shampoo bowls, hair traps, higher hot water demand, laundry hookups | Can the current water heater keep up during busy hours? |
| Any space vacant for months | Stagnant water in pipes, dried-out drain traps, unused branch lines | Has the water system been flushed? Are there capped lines left from old fixtures? |
Find Out What Is Behind the Walls Before Design Is Final
Older commercial buildings often have a mix of pipe materials from different eras of repairs and remodels. Knowing what you have before the design is locked lets you decide what to keep, what to replace, and where new lines should tie in.
A camera inspection of the main drain and building sewer is one of the most useful early steps. It shows cracks, root intrusion, sagging sections, and buildup that a walk-through cannot reveal. If a new restaurant or restroom group will send more water down an old line, you want to know its condition first.
Supply piping deserves a look as well, especially in buildings from before the late 1980s. Before the federal lead ban took effect on June 19, 1986, solders used to join water pipes typically contained about 50 percent lead. The standard tightened again later: the Reduction of Lead in Drinking Water Act, effective January 4, 2014, reduced the “lead free” definition for piping and pipe fittings to 0.25 percent (weighted average with respect to wetted surfaces). Any new pipe, fittings, or fixtures installed during your renovation must meet the current lead-free definition. Solder and flux are subject to a separate limit of 0.2% lead.
| Material | Where It Shows Up | What to Check |
| Cast iron drain pipe | Older drain and sewer lines, often under slabs | Interior scaling, cracks, rusted-through sections, joints that have shifted |
| Galvanized steel supply pipe | Older water lines | Low water pressure from internal rust, leaks at threaded joints |
| Copper with old solder joints | Supply lines in buildings from before 1986 | Joint condition, and whether solder may contain lead |
| PVC or ABS plastic drain pipe | Newer drain lines and past remodels | Proper slope, glued joint quality, mixed materials joined correctly |
| Abandoned or capped branch lines | Anywhere fixtures were removed over the years | Dead-end sections where water sits still |
If the inspection turns up problems on lines you plan to keep, it is usually simpler to handle plumbing repairs while ceilings and walls are already open than after tenants move in.
Accessible Restrooms Are Often Part of the Scope
Many business owners are surprised to learn that renovating a main work or customer area can require restroom upgrades, even if the restrooms were not part of the original plan.
Under federal ADA rules, an alteration that affects the usability of an area containing a primary function must be made so that, to the maximum extent feasible, the path of travel to the altered area and the restrooms, telephones, and drinking fountains serving it are accessible. There is a cost limit on that obligation. Path of travel alterations are deemed disproportionate when their cost exceeds 20% of the cost of the alteration to the primary function area. In practice, that means a renovation budget should set aside room for restroom and drinking fountain work in case it is required. Your architect and the building department will confirm what applies to your project, since North Carolina’s building code also has its own accessibility chapter.
Several accessibility requirements fall directly on the plumbing layout. These figures come from the 2010 ADA Standards for Accessible Design:
| Fixture | Requirement | Plumbing Impact |
| Toilet seat height | 17 inches minimum and 19 inches maximum above the floor, measured to the top of the seat | Fixture selection and flange position |
| Lavatory (sink) height | Front of the rim or counter surface 34 inches maximum above the floor | Sink and counter mounting height, drain height |
| Knee clearance under sinks | At least 30 inches wide with at least 27 inches of vertical clearance | Drain and supply lines must not intrude into the required clear floor space. |
| Pipes under sinks | Water supply and drain pipes under lavatories and sinks must be insulated or otherwise configured to protect against contact | Pipe covers or offset drain assemblies |
| Accessible urinal | Rim no higher than 17 inches above the finished floor | Rough-in height for the urinal carrier |
| Toilet location | Centerline set a specific distance from the side wall or partition | Drain rough-in location, which is hard to move in a slab |
That last row is worth extra attention. In a slab-on-grade building, moving a toilet a few inches can mean cutting concrete. Confirming accessible layouts before rough-in avoids rework. Exact clearances depend on the fixture and mounting configuration; have the designer verify the applicable ADA section.
Kitchens and Food Service: Plan the Grease Interceptor Early
If any food will be cooked, served, or cleaned up in the space, grease control will likely be part of the project. This is one of the items most likely to affect layout, because interceptors can be large and often need outdoor or below-floor space plus access for pumping.
The reason sewer providers care so much: FOG (fats, oils, and grease) is a leading cause of sanitary sewer overflows in North Carolina. The NC Department of Environmental Quality explains that when FOG goes down the drain, it solidifies, reducing and preventing water flow in drains and sewer pipes. DEQ also recommends making sure that all ware washing stations discharge only to an approved grease interceptor.
Many North Carolina cities run formal FOG programs with permitting, sizing rules, and maintenance records. Nearby Hickory, for example, operates its own FOG program for its sewer system. Requirements vary by provider, so before design is final, contact whichever utility serves your building’s sewer and ask what it requires for food service.
Food service also changes water demand. According to the EPA, in restaurants, water use in the kitchen can account for nearly 50 percent of the facility’s total water use. That affects water heater sizing and supply line capacity, not only drains.
A few practical points for owners and landlords:
When you lease to a food tenant, decide in writing who owns, pumps, and maintains the interceptor. Some programs require pumping by a state-permitted service and keeping records on site.
Ask whether the interceptor will serve one tenant or several. Shared interceptors in multi-tenant buildings need clear responsibility for maintenance.
Find out whether a hydromechanical unit under the sink will be accepted, or whether the provider requires a larger in-ground gravity interceptor. The answer changes both cost and site work.
Backflow Prevention on the Water Service
Backflow happens when water reverses direction and flows from a building’s plumbing back into the public water supply. In commercial buildings, the risk comes from connections to equipment or systems that could carry contaminants: boilers, irrigation, fire sprinklers, chemical dispensers, carbonated drink machines, and some medical or lab equipment.
North Carolina takes this seriously. As Winston-Salem’s utility summarizes the rule, the State of North Carolina requires backflow prevention assemblies be installed on all cross-connections to help keep the water supply safe. Local utilities typically add their own requirements for device type, installation, and annual testing. That same utility notes that installation must be performed by an NC licensed plumbing contractor or licensed utility contractor, and all backflow prevention assemblies must be tested when installed.
During a renovation, ask these questions:
Is there an existing backflow assembly on the main water service, and when was it last tested?
Will the new use add equipment that creates a cross-connection, such as a beverage system, irrigation zone, or chemical feed?
Where will testable assemblies go so that testers can reach them each year?
Check with the City of Conover’s utilities department for its specific cross-connection rules before purchasing devices.
Water Heating and Water Quality After a Vacancy
Commercial spaces often sit empty for weeks or months before a renovation starts. Still water in pipes loses disinfectant residual and can approach room temperature, and that combination encourages bacteria growth, including Legionella, the bacteria that causes Legionnaires’ disease.
The CDC states that Legionella grows best between 77°F and 113°F. Its guidance is to store hot water above 140°F, keep hot water in circulation at or above 120°F, and recirculate hot water continuously, if possible, while using scald protection at fixtures. The CDC also warns that slowly moving or stagnant water increases water age, which provides opportunities for Legionella growth.
Renovations can create conditions that support Legionella growth. When fixtures are removed, the branch lines that fed them are sometimes capped in the wall and left in place. Those capped sections, often called dead legs, hold still water that connects to the active system. In many cases, the better approach is to cut abandoned lines back to the main or active branch.
Plan for these steps:
Size the water heater for the new use, not the old one. A salon, restaurant, or medical office can need far more hot water than the retail or office use that came before it.
Consider a hot water recirculation loop if fixtures are far from the heater. It cuts wait times and keeps water moving.
Flush the entire system before the space opens, especially after a long vacancy.
Fixture Efficiency and Ongoing Water Costs
Renovation is the cheapest time to choose efficient fixtures, because you are buying new ones anyway. Commercial water use is a large share of what utilities supply: per the EPA, the commercial and institutional sector is the second largest consumer of publicly supplied water in the United States, accounting for 17 percent of the withdrawals from public water supplies.
Restrooms are where most of that use happens in many buildings. EPA’s WaterSense at Work guide notes that sanitary fixtures and equipment in restrooms and laundries can account for nearly 50 percent of total water use within a facility, and that the opportunity is greatest in older buildings with inefficient fixtures and equipment. For office buildings specifically, EPA lists restrooms, heating and cooling, and landscaping as the three largest uses of water.
The WaterSense label is a simple way to compare products. EPA launched the program to identify products that are independently certified to be at least 20 percent more water-efficient and perform as well as or better than standard models, and the label now covers commercial flushometer-valve toilets as well as faucets, urinals, and showerheads.
One caution: very low-flow fixtures on long, old drain lines may contribute to solids remaining behind in pipes that lack proper slope. This is another reason the camera inspection mentioned earlier is useful before choosing fixtures.
Permits, Inspections, and Licensing in Conover
Conover does not run a separate building inspections office. The Catawba County Building Services Division administers the NC State building regulations and does inspections in the unincorporated areas of the county and for eight municipalities, including Conover. Permits are required for general construction and for electrical, mechanical, and plumbing work. Zoning approval comes first, and the county’s checklist notes that trade applications for electrical, mechanical, and plumbing work are submitted by the tradesmen themselves.
Commercial plumbing work in Catawba County typically moves through several inspection stages. County permit records show plumbing inspections for under-slab work, rough-in, plumbing above ceilings, and a final. One detail that affects scheduling: for some Catawba County commercial projects, final inspections for all trades may need to be scheduled for the same day. Confirm the requirement for your specific permit with Catawba County Building Services. . If your plumber, electrician, and HVAC contractor are not coordinated, the whole project can wait on one trade.
| Inspection Stage | What Is Checked | Timing Tip |
| Under slab | New or altered drain lines before concrete is poured back | Schedule before any slab patching is booked |
| Rough-in | Supply and drain piping inside walls, before insulation and drywall | Coordinate with framing, electrical, and mechanical rough-ins |
| Above ceiling | Piping above hard or dropped ceilings | Must pass before ceiling tiles or drywall close it in |
| Final | Fixtures, connections, and overall installation | All trades call in finals the same day on commercial jobs |
The code edition matters too. As of this writing, the 2018 North Carolina Plumbing Code remains the enforced edition. A 2024 edition has been adopted, but the General Assembly has delayed its start date more than once; one North Carolina municipality reports the new codes will not become effective until some time after March 1, 2027. Ask your design team which edition your plans follow.
Finally, confirm the license class. North Carolina’s plumbing board establishes two classes of licenses: Class I covering all plumbing, heating, and fire sprinkler systems for all structures, and Class II covering plumbing and heating systems in single-family detached residential dwellings. A licensed plumber holding only a Class II license is limited to single-family homes, so commercial work calls for a Class I plumbing contractor. You can look up any contractor’s license on the State Board of Examiners of Plumbing, Heating, and Fire Sprinkler Contractors website.
A Simple Planning Order
| Phase | Plumbing Tasks |
| Before signing a lease or purchase | Ask for any existing plumbing plans, confirm sewer and water providers, and get a drain camera inspection |
| Early design | Confirm the new occupancy and fixture count, accessible restroom layout, grease and backflow needs, and water heater size |
| Permitting | Submit zoning first, then building and trade permits through the Catawba County Permit Center |
| Demolition | Cut abandoned lines back to active piping, and inspect exposed pipe for condition |
| Construction | Pass under-slab, rough-in, and above-ceiling inspections before closing anything in |
| Before opening | Flush the water system, test backflow assemblies, set water heater temperature, and coordinate same-day finals |
Frequently Asked Questions
Can I reuse the existing restroom fixtures in my renovated space?
Sometimes, if they meet current accessibility rules and the fixture count still works for the new use. Older toilets and sinks often fall outside today’s height and clearance requirements, so check them against the ADA figures above before planning around them.
Does a small coffee shop need a grease interceptor?
It depends on your sewer provider’s rules and what you prepare on site. Some North Carolina wastewater programs require grease control for food service establishments, while others base the requirement on the amount or type of grease-generating activity. Ask the utility before you finalize the kitchen layout.
Who pays for plumbing upgrades in a leased commercial space?
That is set by your lease, not the plumbing code. Clarify ownership of items like grease interceptors, backflow assemblies, and water heaters in writing before work starts, along with who handles ongoing testing and pumping.
How long does a building need to sit empty before the water system should be flushed?
There is no single cutoff, but the CDC links stagnant, slow-moving water to Legionella growth. If the space has been vacant for weeks or more, plan a full system flush before opening.
Talk With A&B Plumbing Before Your Renovation Plans Are Final
The plumbing decisions in a commercial renovation are easiest to make early, while layouts can still change and walls are still open. A&B Plumbing is a family-owned, North Carolina-licensed plumbing company, accredited by the BBB and carrying general liability and workers’ compensation insurance. If you are converting, expanding, or updating a commercial space in Conover, contact us to review the existing system, talk through what your new use will require, and plan the work around your permit and inspection schedule.