Running a water or wastewater utility means keeping critical systems online with a small crew, often without a dedicated IT team behind you. When a storm knocks out power or a hard freeze hits a remote site, the first question is what broke. The second is whether you have the replacement part on hand.
Utilities usually diagnose storm damage correctly. The slow part tends to come after that, when a crew waits on a part before the repair can happen. A correct diagnosis with no spare on the shelf still leaves a system down.
This guide covers what to keep on hand, how to plan RTU battery replacement, and how to prepare before storm and freeze season. A short FAQ at the end answers the questions we hear most often.
Why storms and freezes expose spare-parts gaps
Power loss adds its own wrinkle. Mission RTUs delay AC power alarms by about five minutes. If AC power stays off past that point, the AC failure alarm call-out is designed to go out.
That timing matters when a site is hard to reach. Know which alarms are delayed, which go out right away, and who receives each one before the weather turns.
Why small utilities feel this most
Small and mid-sized utilities often run lean. A crew of two or three may cover every site, and one person may be the only one who knows how a particular RTU is set up. When that person is out, or the road to a remote site is closed, the spare-parts question becomes a people question too.
Writing down what you have, where it’s stored, and who can use it turns that risk into a plan that doesn’t depend on one person’s memory.
Build your spare-parts list in four steps
- List every installed model. Include RTU types, radios, and transducers, along with the site where each one is installed.
- Mark single points of failure. If one part failing would take a site offline, it goes on the shelf first.
- Ask suppliers about lead times. Know how long a replacement takes to arrive so the order goes in early enough.
- Store and label. Keep spares in a dry, labeled location, and log each part you take out and return.
Review the list once a year, and again after any major storm or freeze. Each review is a chance to remove parts for equipment you no longer run and add parts for anything you’ve recently installed.
Central stock or a kit at each site?
Both approaches can work. Central stock is easier to count and keep current. A small kit at remote sites can save a long drive when a single part fails. Many utilities use a mix: a full shelf at the main shop and a short kit at the sites that are hardest to reach.
What to keep on the shelf
Start with the parts your system depends on most. The table below lists the four categories that come up most often in storm and freeze planning.
| Spare part | What it supports | Before storm or freeze season |
|---|---|---|
| Radios | Communication between your RTUs and the control system | Confirm spares match the radio models in service |
| Mainboards | Core electronics for RTUs | Confirm spares match the RTU models in service |
| Antennas and cables | The link between radios and their antennas | Check that cable types match the antennas in service |
| Transducers | Level and pressure readings | Confirm spares match the transducer types installed |
Keep the list short and tied to your own layout. A few correct spares beat a long list nobody checks.
Put RTU batteries on the calendar
RTU batteries should be replaced about every five years. Mission RTUs measure and report battery voltage, but that reading is not a real-world full-load test, so don’t treat it as proof of how much runtime is left.
Use this simple schedule for each battery:
| Battery record | What to do |
|---|---|
| Install date | Write it on the site log at installation |
| Replacement due | About five years after the install date |
| Before the due date | Order and stage the replacement, and plan the crew time |
Storm and freeze prep timeline
Plan the work in stages so spares, batteries, and contacts are ready before the weather arrives.
| When | Task |
|---|---|
| October | Count spares against your site list. Confirm RTU battery install dates. |
| November | Confirm after-hours contacts and how alarms reach them. |
| December | Check that remote sites are accessible and that backup supplies are on hand. |
| January to March | Review what was used during the season and restock. |
After the storm: a recovery checklist
Once the weather clears, work through the site in the same order every time. A repeatable routine keeps a bad day from turning into a longer outage.
| Step | What to check |
|---|---|
| Review alarms | Note which alarms fired and whether each one reached the right person |
| Inspect equipment | Check radios, antennas, and cables at each affected site |
| Replace what failed | Use spares on the shelf first, then order what’s missing |
| Update your list | Record what was used and restock before the next season |
How Mission helps utilities prepare
Mission provides managed SCADA for small and mid-sized water and wastewater utilities. 123SCADA, our flagship platform, can send signal-loss alarms set per device, and its SMS alarm notifications let your team acknowledge, silence, and handle multiple alarms. Mission RTUs are built in Marlborough, Massachusetts.
Ready to check your setup? Talk with the Mission team about your spare-parts plan and your monitoring. Technical support: TechSupport@123mc.com or 877.993.1911, option 2. Sales: Sales@123mc.com.
Frequently asked questions
- How many spares should a small utility keep?
- Start with the parts your system depends on most, then count what’s on hand against your site list. There isn’t one right number for every system.
- How often should RTU batteries be replaced?
- About every five years. Record the install date so the replacement is scheduled before it’s due.
- Does battery voltage show how long a battery will last?
- Mission RTUs measure and report battery voltage, but that reading is not a real-world full-load test. Use it as one data point, not the whole answer.
- Who should I contact about spare parts for my system?
- For technical questions, contact TechSupport@123mc.com or call 877.993.1911, option 2. For sales questions, email Sales@123mc.com.
- Should spares be kept at each site or in a central shop?
- Both can work. Central stock is easier to count, and a small kit at remote sites can save a long drive. Many utilities keep a full shelf at the main shop and a short kit at the hardest-to-reach sites.
- What should I do if a part is on backorder?
- Tell your team early, check whether a comparable model is approved for your system, and confirm with technical support before substituting anything. Don’t install a part you haven’t verified.