Tailor Vacuum Truck Size to Your Workload

Almost every pumper is confronted with the question of running with a smaller tank or moving up to a bigger rig. Consider these factors when making an important decision on capacity.
Tailor Vacuum Truck Size to Your Workload
Ronnie and Jennifer Tamez are owners of First Call Septic Services in Battle Ground, Washington. Send your Truck Corner questions to editor@pumper.com.

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When should a pumper trade in a smaller vacuum truck and go big? I had to ask myself this question when I ran around pumping tanks using a 1990 Ford L800 with a 2,200-gallon vacuum tank.

When I was younger, my grandfather told me, “If you have time but no money, start small and spend time behind the windshield. Smaller trucks are less expensive to buy and less expensive to maintain. But after a while, you’ll have more money than time or more work in a day than you can possibly do with your smaller truck. Now, it’s time to buy bigger.”   

Whether or when to go big with your pumping fleet is a big decision, no matter if you’re an owner-operator with one rig or operate many trucks. To help you answer that question, I can share what I have experienced with First Call Septic Services.

We started our septic service company from scratch, with no customers at all. Phones didn’t ring, as we didn’t have an established name or phone numbers in the phone books yet. I was lucky to get six jobs per month. I remember my first December in business: I received one pumping job for the entire month. I had to work two jobs just to make my payments.  


When I was driving the 2,200-gallon truck, typically I could get in two tanks before off-loading at the treatment plant. But if my first job of the day was a 1,500-gallon and my second was also a 1,500-gallon tank, I had to pump the first tank, drive to the disposal site and off-load, and then go to my second appointment. This resulted in a lot of windshield time and fuel expenses.  

As a side note, believe it or not, but my smaller truck got 4-6 mpg and my much larger 4,500-gallon trucks got the same mileage.  

However, with the larger rigs, we can pump three to four tanks before off-loading. This saves the windshield time and fuel — plus, we can provide a higher level of customer service. We don’t have to turn away as much work because we are able to fit them in. In a smaller truck, there was never enough hours in the day, especially if you had a couple of big tanks.

Scheduling the 3-4 appointments can be a challenge as clients like to get us out there at their convenience. We usually start farthest away from the treatment plant with the first job and schedule the second, third, and then fourth moving closer to the treatment plant. Sometimes this works out, but often client schedules may not allow for the most efficient routing plan.   

Going bigger with vacuum trucks has drawbacks.

Yes, you can get more work done per day and achieve better customer service. However, these trucks are significantly more expensive and they require more and costlier maintenance. And from a logistics standpoint, some driveways and homemade bridges cannot accommodate the bigger truck. For this reason, we keep a 2,400-gallon truck on hand, which also makes for a good backup vehicle. When we get on site with the bigger truck and find we should go small, we’ll reschedule a routine maintenance appointment.

On an emergency backup call, however, we’ll have another driver respond right away with the smaller. We don’t charge more for the smaller truck, even though its immediate operating costs are higher. Though I could be wrong and others may disagree, I believe the long-term associated costs of operating the larger trucks offset inefficiencies of the smaller truck.


My first 2,200-gallon truck took just one oil filter and 6 quarts of oil, and it was serviced every 3,000 miles. Not too bad. My 4,500-gallon Mack takes three oil filters and 9-10 gallons of oil. And I have heard of other trucks needing 13-15 gallons. That’s 60 quarts of oil. And about $50 in oil filters. The bigger trucks also have fuel filters that need changing. My Mack has two filters for fuel — another $25.

But wait, there’s more. Bigger trucks have coolant filters, too. My Mack requires a $13 coolant filter. Both the smaller and larger trucks had an air filter, but the smaller truck’s was about $12.  My Mack’s is nearly $80. And since the larger truck is a diesel, we have to maintain the coolant’s nitrite levels to stop cavitation around the cylinders, and that could be anywhere from $5-$10 depending on how much additive you need.

In case you don’t know what cavitation is, I have to tell you how the cylinder is set up. Coolant is in direct contact with the cylinder wall. Diesels have a condition where — on the outside of the cylinder wall as the engine is running — little pockets of air bubbles will open and close. Those air pockets are not unlike boiling water, with one exception: the pressure. The pressure of these bubbles will cause pitting in your liners and can cause your engine to require overhauling.   

And my 2,200-gallon truck ran a Ford 460-cubic-inch gas engine, so it didn’t require any of the maintenance issues or additional costs of the larger trucks. It was very reliable except for its four-barrel carburetor … but don’t get me started on that.


You can see there’s a significant investment to “go bigger.” So the question is when should a pumper consider running a big vac truck? There’s no one right answer, but I go back to the example my grandfather told me years ago. If you have more time than money, stay small. Meaning if you only have one to two jobs per day, stay small. If you have more money than time — meaning if you have a good savings account and you’re working silly, long hours and seven days per week — it’s time to go big.

Get the job done during the workweek, and try to regain your weekends for family time. I have struggled with the work-family balance my entire adult life. To date, we keep growing the company with bigger trucks and more employees to help me regain my weekends.


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