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Here are some things to think about.

If an agricultural irrigation pump has to work against just 5 psi of backpressure from a dirty filter, the motor will use more energy than necessary, reducing efficiency and costing you more. 

When a single solenoid valve fails, the ripple effect moves quickly from just a mechanical glitch to a line item loss on a balance sheet.

There are two ways of dealing with irrigation maintenance: reactive, where you don’t do anything until something fails, and preventative, where you endeavor to address issues before they happen through regular maintenance.

Guess which one’s cheaper in the long run? And that’s the topic of this blog post. We’re going to talk about pre-season, weekly, monthly, and annual maintenance to keep your system running at peak performance.

The Seasonal Rhythm

Pre-Season Maintenance

Before the first seed hits the soil, you need to get your irrigation system ready. This is the Testing and Commissioning Phase, and it’s all about finding the winter surprises before they become summer disasters. And it’s all about preventative maintenance. 

NOSHOK 900 Series (Glycerin Filled)

Check Pressure: This is your baseline inspection for system pressure. Check your Static Pressure (system full, but not flowing) and your Operating Pressure (everything wide open). If your operating pressure is lower than it was last year, you’ve got a "silent leak" or a pump that’s getting worn. Here’s a tip to start: "Keep a Field Journal or a simple notes app on your phone. If Zone 4 had low pressure in August, write it down. You think you'll remember it in February, but you won't. Future-You will thank Past-You for the heads up.

Flush: Don’t just turn your system on and walk away. That’s never a good idea. Open up the end-caps and flush the mainlines. You’d be surprised how much rust, silt, and other contaminants can settle in those pipes over the winter. If you don't flush it out now, it will clog your expensive emitters later.

Prime the Pump: Make sure your pump is primed, and the seals aren't dried out. And remember that a dry start is the fastest way to kill a pump’s lifespan.

In-Season Maintenance

Once the heat is on and the crops are thirsty, you're in the Performance Phase. You aren't looking for major overhauls here. Rather, you're looking for the little things that impact your system and make or break your irrigation system performance.

Trust the Meter: You might not see a leak in a 100-acre field, but the Flow Meter will see it. If your meter shows you're pushing 500 GPM (gallons per minute), but your pressure is dropping, that water is going somewhere it shouldn't – likely a cracked pipe underground.

The Weekly Walkthrough: Once a week, you need to walk your zones. Look for geysers (broken heads), soggy spots (leaks), or dusty spots (clogs). They may sound old school and simplistic, but your boots on the ground are better than any sensor in the world.

Post-Season Maintenance

After the harvest, it’s tempting to just flip the switch and forget it. But please don't do that – that just leads to problems later on. The Decommissioning Phase determines how much you'll have to spend on repairs next spring.

Clean the Filters:  Whether it’s sand media or discs, give your filters a deep, manual scrub. Leaving organic slime or mineral scale on your filters all winter will turn that slime into something resembling solid concrete by the time the season starts.

Evict the Squatters: Mice, rats, and spiders love warm control boxes or dry valve manifold pits. Use steel mesh or professional-grade sealants to block the potential entry points. And before you dismiss this, remember that one chewed-through wire can take down an entire 160-acre pivot.

Drain It Down: If you live anywhere that sees frost, get the water out. Ice expands with enough force to crack cast iron, and that can be an expensive disaster.

The Red-White 435 series of cast iron check valves

Irrigation Pumps & Power

A pump running at 50% efficiency isn't just a minor annoyance. It’s a direct drain on your bank account every single hour it’s running. Let’s talk about pump maintenance.

The Pump House

Your pump works harder than almost any other piece of equipment on the farm. That’s why it's important that you give it a thorough check-up before the season peaks. And here are some things to be on the lookout for.

Listen for Gravelly Sounds: If your pump sounds like it’s chewing on glass, you’ve likely got . Cavitation happens when the pump can't get enough water, perhaps due to a clogged intake screen or air in the line. Cavitation will literally devour your impeller if you don't fix it.

The Packing Gland Drip: On older centrifugal pumps, you actually want a little drip (up to about one drop per second) to keep the packing cool and avoid burning out the shaft. If it’s a geyser instead of a drip, tighten the gland nuts slightly.

Alignment Check: You can use a simple straightedge to make sure that the motor and pump shafts are lined up correctly. Keep in mind that even a tiny "wobble" creates heat and vibration that will eventually snap a coupling or destroy a bearing.

Electrical Systems

Irrigation systems are often at the end of the line on the power grid. When the voltage drops, the amps (heat) go up. And it's that heat that kills motors.

Tighten the Terminals: Vibrations from the pump can loosen electrical lugs over time. A loose wire creates high resistance, leading to serious problems with charred insulation and, eventually, a fire or a blown motor. Give every screw a quarter-turn to make sure it's still snug.

Grounding is Life: Agriculture involves water and metal, which is a deadly combo. Ensure your grounding rod is still connected and hasn't been hit by a mower or corroded away.

Pump Efficiency

A worn pump might still move water, but it’s doing it inefficiently. And that costs money. Here’s how to keep that pump running efficiently.

Amp Draw Test: Use a standard multimeter to check the motor’s current draw while it’s running under full load. Compare the current draw to information on the motor’s nameplate and historic data. If it’s pulling significantly more amps than it should, your pump is struggling. This may be caused by many factors, from worn impellers to a partially blocked intake.

Pressure Gauge Health: Don’t trust a 10-year-old gauge that’s been sitting in the sun. Inspect, calibrate and replace your main pressure gauges regularly. They are your best way you can truly see what’s happening inside those pipes, and you need a reliable, trustworthy gauge for that.

Filtration & Fertigation: Keeping the Lines Clean

The filtration system is the only thing standing between your expensive drip lines or nozzles and a total (and expensive) system failure caused by sand, algae, or mineral scale. When you use fertigation (injecting fertilizer into the water) you’re essentially feeding the system, but if you don’t do it right, you’re just feeding a massive clog.

Filtration

Whether you're using sand media, discs, or screens, the rule is simple: A clean filter is a cheap filter.

The "Pressure Differential" Rule: Don’t guess when to clean. Check the gauges on both the inlet and outlet. If the difference is more than 5–7 PSI, your filter is choked. Most automatic systems backwash at this point, but if yours is manual, it’s time to backwash, clean or inspect your filter.

Sand Media Maintenance: Open the tanks once a year and look at the sand. If it feels like concrete or has signs of channeling, it’s not filtering. You should expect to lose a few inches of sand every season. so top it off with the specific grade recommended by the manufacturer.

The Disc Filter Scrub: If you’re using disc filters, a simple rinse usually does the trick. But if they're covered in white crust or green slime, a simple water hose won't cut it. Soak the disc stack in a mild acid solution (for minerals) or a chlorine bath (for organics) to get those filters back to 100%.

Fertigation

is a game-changer for yield, but it's also the leading cause of a different type of clog: chemical.

The Jar Test: Before you dump a new fertilizer into your stock tank, mix a small sample with your irrigation water in a glass jar and let it sit for an hour. If it turns cloudy or develops flakes at the bottom, it will do the same thing inside your pipes. This is often caused by high pH water reacting with phosphorus or calcium.

The 4-Inch Rule: Never let your injector's suction hose sit at the very bottom of the fertilizer tank. Keep it about 4 inches above the bottom of the fertilizer tank. This prevents the sludge at the bottom of the tank from being sucked into your pump and filters.

Post-Fertilization Flush: Never turn off the water immediately after you finish injecting fertilizer. You need to run clean water through the lines for at least 30 minutes to rinse out the pipes after injecting fertilizer. If you leave fertilizer sitting in the lines, you're essentially making it possible for algae and bacteria to clog your emitters.

Chemical Shock

If you’re pulling from a pond or a canal, biological growth (i.e., algae and biofilm) is going to be your enemy. If flushed water looks like a green soup, you might need a maintenance dose of chlorine. A low-level shock (aiming for 1–2 ppm of free chlorine at the very end of the line) kills the slime before it can take root. And if you have hard water, calcium scale will eventually narrow your pipes. Injecting a bit of acid to bring the pH down below 7.0 can keep those minerals in solution so they flow out of the emitters instead of sticking to them.

Irrigation Maintenance Checklists

Now, let’s look at some checklists to help guide you through maintaining your agricultural irrigation system.

Main Irrigation Checklist

Pre-Season Checklist

In-Season Checklist

Post-Season Checklist

Weekly Irrigation Performance Log

Use this log to record your weekly readings for each irrigation zone or field block. Fill in your baseline GPM and operating PSI during the first week of the season. Each subsequent week, compare your readings to that baseline. A flow rate that is higher than baseline indicates a potential leak. A flow rate that is lower than baseline indicates a potential blockage or clogged emitter. A filter pressure differential greater than 7 PSI means the filter needs cleaning. Keep this log on-site for reference during service calls.

Frequently Asked Questions

How often should I check my irrigation filter pressure?

Check your filter pressure differential every week during the active irrigation season. Measure the PSI at both the inlet and the outlet of the filter. If the difference between the two readings exceeds 7 PSI, the filter needs to be cleaned. Waiting longer risks a pressure drop severe enough to reduce flow to your emitters or cause pump strain.

What causes cavitation in an irrigation pump?

Cavitation is caused by the pump trying to pull more water than the intake can supply. The most common causes are a clogged intake screen, a partially closed suction valve, or air entering the line through a loose fitting. The symptom is a gravelly or rattling sound from the pump housing. Left unaddressed, cavitation erodes the impeller and shortens pump life significantly.

When should I perform an amp draw test on my irrigation pump motor?

Perform an amp draw test at the start of every season as part of your pre-season checklist, and then monthly during the active season. Use a clamp meter on the motor leads and compare the reading to the nameplate amperage rating. Readings consistently above the nameplate value indicate motor strain, worn bearings, or a pump that is working against excessive head pressure. Catching this early prevents unplanned motor failure during peak season.

What is the correct way to flush fertilizer lines after fertigation?

After every fertigation cycle, run clean water through the irrigation lines for a minimum of 30 minutes. This rinses residual fertilizer out of the pipes, emitters, and filters before it can dry and crystallize. Fertilizer left sitting in lines is the leading cause of emitter clogging and provides a substrate for algae and bacterial growth. The 30-minute flush time applies to standard drip systems; longer mainlines may require additional flushing time.

Conclusion

Preventive maintenance is critical for achieving good results and performance from your agricultural irrigation system. Whether you're listening for signs of cavitation or checking pressures along the line, you’ll find that addressing potential issues before they happen is cheaper and safer for your equipment. It reduces downtime, improves efficiency, and the cost of maintenance is inexpensive compared to equipment repairs.

91ÊÓƵ has supplied irrigation valves, pressure gauges, flow meters, solenoid valves, and actuators to agricultural operations across the country for over 50 years. If you have a question about a specific component, our engineers are available to help you select the right product for your system.

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Gilbert Welsford, Jr

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Gilbert Welsford, a renowned valve industry expert and third-generation owner of FS Welsford Company, is the visionary behind 91ÊÓƵ, a leading platform for valve-related products. Gilbert's profound understanding of fluid dynamics and precision engineering plays a pivotal role in designing and applying various valve types. Known for his collaborative approach and outstanding communication skills, he builds strong relationships across multiple sectors and consistently ensures successful project outcomes. Committed to innovation and excellence, Gilbert remains at the forefront of industry advancements, consistently delivering solutions that exceed expectations.