The Math Behind the Numbers
Every default in this calculator is sourced. Here's each formula laid out step by step — with the reasoning behind every number we chose.
WHERE THE DEFAULT NUMBERS COME FROM
These are the values pre-filled in the calculator. Every one of them can be changed — and you should change anything that doesn't match your plant.
Variable | Default | Why we used it |
|---|---|---|
Trucks | 10 | Your input |
Loads / truck / day | 2 | Your input |
Operating days / yr | 250 | 50 weeks × 5 days — standard U.S. ready-mix schedule |
Manual wash time | 12 min | Industry range is 5–15 min. We used the midpoint — not the best case. Modern Pumping Today case study. |
Manual hose flow rate | 45 gpm | Standard concrete washout hose spec |
Manual water / wash | 540 gal | 12 min × 45 gpm. Shumaker literature puts the range at 150–600 gal. |
Load & Go cycle time | 1.0 min (rear) / 1.5 min (front & dual) | |
Automated water / wash | 67.5 gal (front/dual) / 45 gal (rear) | 45 gpm × cycle time |
Truck & driver cost / hr | $88/hr | Fully loaded cost: wages, benefits, fuel, insurance, depreciation & overhead. NRMCA Performance Benchmarking Survey (via Concrete Products, 2023) pegs ready-mix operating cost at $1.28/min = $76.80/hr in 2020 dollars. Adjusted to 2024 using BLS PPI for trucking (~4.5%/yr compounded) = ~$91/hr. We default to $88 as a conservative mid-point. Driver-only wage is ~$28/hr (SalaryExpert 2026). |
Water + wastewater cost | $0.01336 / gal | EPA WaterSense 2024 national commercial average: $6.13/1,000 gal supply + $7.23/1,000 gal disposal = $13.36/1,000 gal combined. |
Sales price / yd³ | $130 | Modern Pumping Today case study |
Average load size | 9 yd³ | Industry-standard mixer capacity |
1 — Labor & Time Savings
The biggest savings category. Every minute a truck sits at the wash rack is a minute of labor, fuel, and equipment cost running on the clock.
Step 1 — How much time does each wash save?
Time saved per wash = Manual wash time − Load & Go cycle time
Example: 12 min − 1.5 min = 10.5 min saved per wash
Step 2 — Scale across the whole fleet for a full year
Annual minutes saved = Time saved/wash × Loads/truck/day × Trucks × Days/yr
Example: 10.5 × 2 × 10 × 250 = 52,500 min/yr
Step 3 — Convert hourly cost to a per-minute rate
Cost per minute = Cost per hour/60
Example: $88 ÷ 60 = $1.47 per minute
Step 4 — Annual labor savings
Labor savings / yr = Annual minutes saved × Cost per minute
Example: 52,500 × $1.267 = ≈ $66,500 / yr
Why fully loaded cost? Because the truck doesn't stop costing money while it's sitting at the wash rack. Fuel, insurance, and driver benefits are all running. Using driver wage alone understates the true cost by 2–3×. If your operation runs differently, change the hourly rate input and the number will adjust.
2 — Water & Wastewater Savings
Manual washout uses a lot of water — and you pay twice: once to buy it and once to dispose of it. The Load & Go cuts water per wash by 70–80%.
Step 1 — Water saved per wash
Water saved / wash = Manual water − Automated water
Example: 540 gal − 67.5 gal = 472.5 gal saved per wash
Step 2 — Scale to annual volume
Annual water saved = Water saved/wash × Loads/truck/day × Trucks × Days/yr
Example: 472.5 × 2 × 10 × 250 = 2,362,500 gal/yr
Step 3 — Apply combined water + wastewater rate
Water savings / yr = Annual water saved × $0.01336 / gal
Example: 2,362,500 × $0.01336 = ≈ $31,550 / yr
The $0.01336/gal figure combines supply ($6.13/1,000 gal) and wastewater disposal ($7.23/1,000 gal) into a single rate — per EPA WaterSense 2024 national commercial averages. If your municipality charges a different rate, enter it in the calculator and this will update.
3 — Extra Delivery Revenue (optional)
Faster washouts mean trucks return to the plant sooner. Some operations use that recovered time to squeeze in an additional load. This section only appears if you turn on that toggle.
Step 1 — Time recovered per truck per day
Daily time saved / truck = Time saved/wash × Loads/truck/day
Example: 10.5 min × 2 = 21 min / truck / day
Step 2 — Can that time fit another delivery? (conservative floor)
Extra loads / truck / day = FLOOR (Daily time saved / truck)/Round-trip delivery time
Example (60-min round trip): FLOOR(21 ÷ 60) = 0 extra loads
Step 3 — Annual extra revenue
Extra revenue / yr = Extra loads/truck/day × Trucks × Days/yr × Revenue per load
Example: 0 × 10 × 250 × 130= $0 / yr
We use FLOOR() — meaning if the saved time doesn't fully cover another round trip, we count zero, not a fraction. We also calculate per-truck, not fleet-wide. This prevents the number from being inflated by pooling minutes across trucks that can't actually share a route. Change your round-trip time and watch this number move.
4 — Total Annual Benefit & Payback
Add the three savings streams together to get your total annual benefit, then divide equipment cost by that number to see payback in years.
Total Annual Benefit
Annual Benefit = Labor Savings + Water Savings + Extra Revenue
Example: $66,500 + $31,550 + $0 = $98.050
Payback Period
Payback (years) = Equipment Cost/Annual Benefit
Example: $150,000 ÷ $98,000 = 1.53 years
Year-1 ROI %
ROI % = (Annual Benefit/Equipment Cost) ×100
Example: ($98,000 ÷ $150,000) × 100 = 65%
A note on what's not shown: the calculator quietly includes a $5,000/yr maintenance reserve in the annual benefit calculation. That keeps the payback figure honest — a clean machine needs upkeep, and we'd rather show you a conservative number than have a surprise later.
5 — Fleet Reduction (alternative scenario)
Instead of using recovered time for extra deliveries, some operations choose to run fewer trucks at the same output. This is an either/or scenario — don't add this to the numbers above.
Fleet-wide daily time recovered
Fleet minutes saved / day = Time saved/wash × Loads/truck/day × All trucks
ample: 540 gal − 67.5 gal = 472.5 gal saved per wash
How many trucks could you remove?
Trucks removable = FLOOR (Fleet minutes saved / day)/(Hours/day × 60)
FLOOR rounds down — we only count a truck as removable if the time savings fully covers a complete truck-day.
Step 3 — Apply combined water + wastewater rate
Fleet savings / yr = Trucks removed × Cost/hr × Hours/day × Days/yr
xample: 2,362,500 × $0.01336 = ≈ $31,550 / yr
All defaults are sourced and cited above — swap in your own numbers any time. This is an estimate, not a guarantee. Contact your Shumaker rep for exact equipment pricing.