One maintenance technician per 100 units sounds like a staffing level. It's really a statement about time.

A full-time technician may be paid for about 2,080 hours a year. Spread across 100 units, that's roughly 21 paid hours per apartment per year, before time off, training, travel, coordination and other non-work-order time. At one technician per 150 units it's about 14 paid hours. At one per 200, about 10.

Put that way, the question stops being "what's the right ratio?" and becomes "how many hours does each of my apartments actually need?" That question has an answer, and it's sitting in your work order history.

The ratios in circulation don't agree

Published guidance and industry discussions produce a wide range of staffing numbers, which is exactly why a single ratio can be misleading. Some sources suggest fixed starting ratios, while operators report very different staffing levels depending on the property, the workload and the scope of work kept in-house.

The Houston Apartment Association, an affiliate of the National Apartment Association, traced the most-quoted rule back to its source, and says bluntly that the number quoted secondhand is wrong by half. NAA's 2020 Staffing Considerations guidance states it as one office staff and one maintenance staff per 100 units: two people per 100 units, not one. It adds a rounding rule, adding a team member once a property is 51% or more of the way to the next hundred units, and a floor for small communities of part-time office and maintenance staff at around 40 units.

The "one per 100" version heard in budget meetings, according to HAA, matches a different NAA document: a 2022 opinion column that argued the ratio model is obsolete.

So the version most often quoted in maintenance staffing discussions is not the wording of NAA's 2020 guidance, and a later NAA column argued against the model altogether. Neither is a current measurement. HAA's advice is to use the ratio as a budgeting starting point and then staff to the equipment list, the turn calendar and the on-call rotation.

That's the right instinct. The rest of this article turns it into a calculation.

What a ratio can't see

Two 300-unit communities can hold the same ratio and be completely different jobs.

One was built in 2019, with individual package units, new appliances still under warranty, and a turn process that contracts out paint and flooring. The other was built in 1982, with central boilers, a pool, aging appliances, galvanized plumbing and in-house turns.

A ratio treats them as identical. Their work orders won't. The differences that drive workload are all invisible to a unit count:

• Building age and system condition. Older properties may have different equipment conditions, maintenance requirements and repair workloads.

• Amenities. Pools, fitness centers, gates and elevators each carry recurring work.

• Turn volume and scope. How many units turn each year, and whether turns are done in-house or contracted.

• Scattered sites. A technician covering several properties spends a real share of the day driving.

• On-call load. Somebody carries the phone every night and weekend, and after-hours calls take longer than daytime ones.

• Certification. Some work can only be done by particular technicians, which the next section covers.

The certification constraint

Ratios count technicians. Some work can only be done by particular technicians.

Some maintenance work has specific certification or licensing requirements. In the US, for example, the Environmental Protection Agency's Section 608 rules require technicians who maintain, service, repair or dispose of equipment that could release refrigerants to be certified, subject to the regulation's exceptions. Other electrical, plumbing and trade requirements vary by jurisdiction.

HAA makes the practical point sharply: a community staffed at a textbook ratio may still have only one person who can legally open a refrigerant circuit, which makes the on-call rotation for that work a rotation of one.

So count appropriately certified technicians separately from technicians. For properties that rely on in-house refrigerant work, the number of appropriately certified technicians can become a staffing constraint.

Build the estimate from workload

Here's the method. You're comparing two numbers: the hours of work your property generates, and the productive hours one technician can supply.

Step 1: Hours of demand

Pull the last 12 months from your work order history. Five categories cover most maintenance teams:

If your work orders don't record time, that's the first thing to fix. Without it, every staffing conversation is an argument between opinions.

Step 2: Productive hours per technician

A technician paid for 2,080 hours doesn't have 2,080 hours to spend on work orders. Subtract:

• Paid time off and public holidays

• Training and certification time

• Meetings, parts runs, vehicle and shop time

• Travel between sites, for scattered portfolios

What remains is productive capacity. Measure it from your own payroll and work order data rather than assuming it.

Step 3: Divide

Demand hours divided by productive hours per technician gives the headcount the workload needs.

A worked example

These figures are illustrative, chosen to show the method, not to serve as benchmarks. Use your own.

A 240-unit community built in the 1990s:

If each technician supplies about 1,500 productive hours a year, the workload needs 2.7 technicians.

Now compare that with what the ratios would have said. The correctly stated NAA rule, one maintenance staff per 100 units, gives 2.4. One per 150 gives 1.6. The first is close; the second would leave this property more than a full person short, and the shortfall would show up as a growing backlog, slipping preventive work and slower turns.

Change one decision and the answer moves. If this property contracted out more of its turn work, cutting in-house turn hours from 1,296 to 300, total demand falls to 3,120 hours and the requirement drops to about 2.1 technicians. Whether to insource or outsource particular work is a separate decision with its own trade-offs, covered in our guide to property maintenance services. The point here is that the staffing number follows from it, and a ratio can't reflect it.

Staff for the busy season, not the average month

Annual hours hide peaks. If a large share of your leases expire in the same few months, turn workload concentrates there, often alongside peak heating or cooling demand.

A team sized for the annual average will be short in exactly those weeks. Look at your expiration profile before settling a headcount, and decide in advance how peaks will be covered: seasonal help, contracted turns or planned overtime. We covered reading that profile in your leasing season was decided twelve months ago, and how turn work is sequenced in the turn starts at notice, not at move-out.

Budgeted seats aren't filled seats

A staffing model assumes the seats are occupied. They often aren't.

HAA cites the 2025 RCLCO National Real Estate Compensation and Benefits Survey, as reported by NAA, which found total turnover among onsite property-level employees reached 29.2% over the prior year. That figure covers onsite real estate staff broadly, not maintenance alone. Even so, turnover can create periods when a budgeted position is unfilled or a replacement technician is still getting up to speed.

A team budgeted at three technicians with one seat empty for four months averages about 2.67 across the year. HAA's advice is to measure staffing against filled seats averaged over the year, not the budget. Build vacancy into the model, rather than discovering it in the backlog.

Signs the team is understaffed

The workload model tells you what you need. These signals tell you whether what you have is enough:

• Backlog getting older, not just longer

• Preventive maintenance slipping, as reactive work crowds it out

• Overtime rising as a share of maintenance payroll

• Work orders reopening, because rushed fixes don't hold

• Turn times lengthening in peak months

• On-call nights per technician climbing, which is also a retention risk

Most of these are standard maintenance KPIs, defined with formulas in our guide to facility management KPIs. Read them here as staffing signals: one slipping on its own might be a process problem, several moving together usually means the hours don't add up.

A staffing ratio is a guess about time dressed as a headcount. The work order history already holds the real answer: how many hours your buildings generate, of what kind, in which months.

The obstacle is usually that the history can't answer the question. Work orders without time recorded against them, PM tasks tracked in one place and turns in another, and on-call callouts that never make it into any system.

RIOO's service request and task management records work orders from submission through assignment to completion, with performance analytics across properties. Maintenance planning and scheduling holds the preventive workload alongside it, and dashboards and reports show maintenance trends and completion data that can help managers build a workload-based staffing model.

Before the next budget cycle, try filling in the demand table above for one property from your own records. If you can complete it in an afternoon, you can staff to your workload. If you can't, that's the first problem to solve.

Frequently asked questions

Q1. How many maintenance technicians do you need per apartment unit?
There's no single correct ratio. Published guidance and operator experience vary widely. The Houston Apartment Association reports that NAA's own 2020 guidance states one office and one maintenance staff per 100 units. The more reliable approach is to calculate the hours of work your property generates and divide by the productive hours one technician supplies.

Q2. What is the NAA maintenance staffing ratio?
According to the Houston Apartment Association's review of NAA's 2020 Staffing Considerations guidance, the rule is one office staff and one maintenance staff per 100 units, with a rounding rule and a floor for small properties. A 2022 NAA opinion column argued that the ratio model is obsolete.

Q3. How do you calculate maintenance staffing needs?
Add up annual hours for reactive work orders, preventive maintenance, in-house turn work, on-call callouts and recurring site work. Divide by the productive hours one technician supplies after time off, training, meetings and travel. Adjust for seasonal peaks and for seats that may sit vacant.

Q4. Does every technician need refrigerant certification?
In the US, EPA Section 608 certification is required for technicians who maintain, service, repair or dispose of equipment that could release refrigerants, subject to the regulation's exceptions. Other trade requirements vary by jurisdiction. Count appropriately certified technicians separately, since they can limit who can cover certain work and on-call shifts.

Q5. What are the signs a maintenance team is understaffed?
An aging backlog, slipping preventive maintenance, rising overtime, reopened work orders, lengthening turn times and more on-call nights per technician. Several of these moving together usually means demand hours exceed capacity.