If you’ve ever stood by a dry well, watching your submersible pump sputter then go silent, you know that small, unglamorous maintenance tasks are the quiet guardians of a reliable pumping system. As a submersible pump supplier, I’ve spent 12 years on job sites, troubleshooting everything from residential sump pump failures to agricultural irrigation pump breakdowns—and 80% of those issues trace back to something most people overlook: improper lubrication. Submersible pumps operate in dark, high-pressure, water-submerged environments, so their internal components don’t get the same gentle care as above-ground pumps. Skipping the right lubrication, or using the wrong type, is like running a car with no oil: it’s only a matter of time before parts seize, bearings wear out, and you’re left with a costly, premature pump replacement. Today, I’m breaking down the science of how to lubricate a submersible pump, step by step, along with the mistakes I see customers (and even some inexperienced techs) make every single time. Submersible Pump
First, let’s get clear on a critical detail: not all submersible pumps require the same lubrication. For most standard submersible pumps—think residential sump pumps, light commercial effluent pumps, or agricultural irrigation pumps used in clean water wells—we design them with sealed, pre-lubricated motor bearings that don’t need field lubrication during their normal service life. That’s why I cringe when I get a call from a customer who’s taken their brand-new 1 HP sump pump apart to “add oil like their old above-ground pump.” Adding grease or oil to a sealed motor voids our warranty, and 9 times out of 10, it leads to seal damage that lets water seep into the motor winding, shorting it out. The only submersible pumps that need field lubrication are heavy-duty models: deep well submersible pumps for high-flow agricultural irrigation, wastewater handling pumps with oversized mechanical seal assemblies, or custom engineered pumps used for municipal water transfer. If you’re working on one of these, lubrication is non-negotiable. If you’re working on a residential sump pump, your only lubrication task is checking the external parts—like the handle or power cord strain relief—never the interior motor. Let’s lock that in first because misinformation here is the number one cause of avoidable pump failures.
Now, before you touch any part of your submersible pump, you need to gather the right tools and materials, and follow the absolute non-negotiable safety rules. Submersible pumps run on high-voltage electricity, and if they’ve been sitting in water, there’s always a risk of residual current—even when the power is off. First, disconnect the power source entirely. Don’t just turn off the circuit breaker labeled “well pump” or “sump pump”; go to the main electrical panel, flip the breaker, and even better, tape it in the “off” position so no one accidentally turns it on while you’re working. If you’re working on a deep well pump, the last thing you want is a surprise jolt or a pump that shifts and falls down the well. Next, wear personal protective equipment (PPE): heavy rubber gloves, safety goggles, and steel-toe boots. You’ll be lifting a heavy, wet pump (most submersible pumps weigh 50 to 200 pounds, even the small ones), and working around old, corroded metal that can catch gloves or scratch skin. Now, list the supplies you’ll need for lubrication, specific to heavy-duty submersible pumps: the correct lubricant (this is non-negotiable—always check the pump’s specification sheet, not Google), a grease gun with a narrow, needle-nose fitting (standard grease guns won’t fit through the small lubrication ports on modern pumps), a clean lint-free cloth, a basin to catch any water that drains from the pump housing, a small wire brush for cleaning port threads, and a marine-grade thread sealant (PTFE tape) for the port caps. Never use household grease or automotive oil for submersible pumps. These pumps operate in water, often at temperatures 20 to 30 degrees higher than above-ground pumps, and are exposed to chemicals in wastewater or mineral deposits in well water. We specify either lithium complex grease with extreme pressure (EP) additives for most bearing applications, or food-grade, NSF-approved grease for pumps used in drinking water wells. I once had a customer use generic wheel bearing grease on a deep well pump he installed for his family’s drinking water—six months later, the grease broke down, mixed with the well water, and clogged his irrigation lines. Stick to the lubricant we recommend, or the one listed on your pump’s serial number tag.
Now, let’s walk through the step-by-step process, starting with preparing the pump for lubrication. First, if the pump is still in the well or sump basin, you’ll need to pull it. For sump pumps, this is easy: unplug it, lift it out of the basin, and set it on a flat, dry surface. For deep well pumps, this requires disconnecting the power cable and the discharge pipe at the well head, then slowly pulling the pump up with a rope or hoist—never let it drop, as that can damage the impeller or seal. Once the pump is out, set it on a workbench or saw horses, making sure it’s stable and won’t roll. Give the entire outside a wipe down with a clean cloth to remove dirt, mud, or well sediment—this prevents any debris from falling into the lubrication ports during the process. Now, locate the lubrication ports. On most heavy-duty submersible pumps, you’ll find two ports: one for the drive end bearing and one for the non-drive end bearing, usually located on the side of the motor housing, marked with small “L” or “GREASE” stamps. If you can’t find them, check the pump’s manual, or give us a call (we’ll always help a fellow pump owner or tech, no charge). The ports are small, so you’ll need to clean them thoroughly before opening. Take your small wire brush and gently scrub the port and the surrounding area to remove any rust, mineral deposits, or old grease that’s caked on. Then, take a clean cloth and wipe the port until it’s completely free of debris—if you skip this step, you’ll push that dirt into the pump’s bearings when you inject grease, causing more wear.
Next, the actual lubrication step, and this is where almost everyone messes up. First, remove the port cap with a small wrench or screwdriver. Set the cap in a clean, safe place so you don’t lose it (these are tiny, easy to misplace). Now, attach the needle-nose grease gun to the port. Push it firmly into place, twisting slightly to ensure a tight seal—if there’s a gap, grease will leak out, and you won’t know how much you’re adding. Now, pump the grease gun slowly, only a quarter-turn per pump, or about 1 to 2 grams of grease at a time. Stop every few pumps and check the old grease that’s coming out of the port’s relief valve (most pumps have a small bleed hole next to the lubrication port). When the new, clean grease comes out, free of any dark, gritty, or discolored old grease, you’re done. This is critical: never over-grease. Over-lubricating is a far more common mistake than under-lubricating, and it’s just as bad. Too much grease creates excess heat, causes seals to fail, and can force grease into the pump’s impeller or seal area, blocking flow. For most deep well pumps, you’ll only need 5 to 10 grams of grease per bearing—less than a teaspoon. If you’re not sure, stop when you see clean grease coming out the bleed port. Once you’re done, remove the grease gun, and immediately replace the port cap, tightening it snugly. Now, move to the second bearing, and repeat the exact same process.
Wait—one more critical step: checking the mechanical seal. Before you put the pump back, inspect the mechanical seal, which is located between the motor and the pump impeller. A bad seal is the number one reason lubrication goes wrong, because if water is already getting into the seal area, adding grease won’t fix that—it’ll just trap water inside, causing motor failure. Take a close look at the seal: it should be smooth, with no cracks, chips, or corrosion. If you see any damage, replace the seal before you lubricate or reinstall the pump. I’ve seen technicians lubricate a pump with a bad seal, put it back in service, and have it die within a week—all because they skipped the seal check.
Once you’ve lubricated the bearings and checked the seal, put the pump back together carefully. For sump pumps, set it back in the basin, make sure the discharge pipe is connected, and the power cord is not pinched. For deep well pumps, lower it back into the well slowly, making sure the power cable is secured to the pipe so it doesn’t get damaged, and the discharge pipe is tight. Once the pump is back in place, turn the power on and run it for 5 to 10 minutes. Watch for leaks around the lubrication ports, the seal, and the discharge pipe. Listen for any unusual noises—grinding, squealing, or clicking—that could mean you over-greased, or there’s another issue. If it runs smoothly and without leaks, you’re done.
Now, let’s talk about the maintenance schedule. How often do you need to lubricate your submersible pump? For most residential pumps, if you followed our guideline and have a sealed, pre-lubricated motor, you’ll never need to lubricate the interior during the pump’s lifespan (usually 8 to 15 years, with proper care). For heavy-duty agricultural or municipal pumps, lubrication is required every 12 to 18 months, or after 2,000 hours of operation—whichever comes first. If you run your pump 24/7 for irrigation, that means it will need lubrication every 8 to 10 months. I recommend writing the lubrication date on a sticker and sticking it to the pump’s control box, so you don’t forget.
Now, let’s address the mistakes I see most often, because these are the ones that cost people the most money. First, using the wrong lubricant. As I mentioned earlier, generic automotive grease or oil is not designed for submersible pumps. It breaks down faster in water and high temperatures, and can leave residue that clogs components. Second, over-greasing. I had a customer last year who lubricated his deep well pump, added a whole tube of grease because he thought more was better, and the pump seized up within 24 hours. We had to pull the pump, disassemble it, clean all the excess grease out, and replace the bearings—costing him $800 in service fees, on top of the pump being out of service for three days while he waited for parts. Third, not pulling the pump to lubricate. Some people try to lubricate their deep well pump from the top, through the well head, without pulling it out. This almost never works, because the ports are located on the side of the motor, and you can’t get a tight seal on the grease gun without being able to align it properly. Fourth, skipping the seal check. A bad seal will turn a routine lubrication into a motor replacement. Fifth, ignoring the small parts, like port caps. If you lose a port cap, water and sediment will get into the bearings the next time you run the pump, leading to early failure.
If you’re not comfortable lubricating your submersible pump yourself, or you’re not sure if your pump even needs lubrication, don’t hesitate to reach out. As a submersible pump supplier, we’ve worked on thousands of pumps, from small sump pumps to large municipal units, and we’re here to help. We can walk you through the process over the phone, recommend the exact lubricant for your model, or connect you with a certified tech in your area if you’d rather have a professional handle it. Routine lubrication is one of the easiest ways to extend the life of your submersible pump, saving you thousands in replacement costs and downtime. Whether you’re a homeowner with a sump pump, a farmer with an irrigation well, or a business owner with a commercial wastewater system, taking 30 minutes to properly lubricate (or confirm your pump doesn’t need it) is a small investment that pays off big time.
If you have questions about your specific submersible pump’s lubrication requirements, or you’re looking to purchase a new pump for residential, agricultural, or commercial use, feel free to get in touch with our team to discuss your needs and request a custom quote.
Self-balancing Multistage Pump References:
- Hydraulic Institute. (2021). Submersible Pump Maintenance Guidelines. Parsippany, NJ: Hydraulic Institute.
- National Water Well Association. (2020). Submersible Pump Operation and Care Manual. Dublin, OH: National Water Well Association.
- Underwriters Laboratories (UL). (2019). Standard for Safety for Submersible Pumps (UL 778). Northbrook, IL: Underwriters Laboratories Inc.
Hunan Sanchang Pump Co., Ltd.
Hunan Sanchang Pump Co., Ltd. is one of the most reliable submersible pump manufacturers and suppliers in China, also supports customized service and OEM&ODM service. Welcome to buy CE certified submersible pump made in China here and get pricelist from our factory. For price consultation, contact us.
Address: No.517, Xiangfu East Road, Yuhua District, Changsha City Hunan
E-mail: info@sanchangpump.net
WebSite: https://www.sanchangpump.net/
