The number of drop pipes depends on your well depth and where the pump cylinder needs to be positioned. Here's how to calculate your needs.
Basic Calculation
Formula
Drop pipe length needed = Water depth + submergence depth
- Position cylinder below static water level
- Typical submergence: 10-30 feet below water
- Deeper is often better for low-yield wells
Drop Pipe Lengths Available
| Kit | Length | Use Case |
|---|---|---|
| 27" Drop Pipe Kit | 2.25 ft | Fine adjustment |
| 54" Drop Pipe Kit | 4.5 ft | Standard length |
| 105" Drop Pipe Kit | 8.75 ft | Fewer connections |
Configuration Examples
Example 1: 100 ft Static Water Level
Goal: Position cylinder 20 ft below water (120 ft total)
Option A (fewer connections):
- 13 × 105" kits = 113.75 ft
- 1 × 54" kit = 4.5 ft
- 1 × 27" kit = 2.25 ft
- Total: 120.5 ft
Option B (standard kits):
- 26 × 54" kits = 117 ft
- 1 × 27" kit = 2.25 ft
- Total: 119.25 ft
Example 2: 200 ft Static Water Level
Goal: Position cylinder 25 ft below water (225 ft total)
Configuration:
- 25 × 105" kits = 218.75 ft
- 1 × 54" kit = 4.5 ft
- Total: 223.25 ft
Why Cylinder Position Matters
Above Water = Problem
If cylinder is above water level:
- Pump will draw air
- No water production
- Seals run dry
Just Below Water = Marginal
If cylinder barely submerged:
- Vulnerable to water level drops
- Seasonal variation issues
- May pump air during drawdown
Well Below Water = Ideal
With adequate submergence:
- Reliable water production
- Seasonal buffer
- Handles well drawdown
Cylinder Submergence Guidelines
| Well Type | Recommended Submergence |
|---|---|
| High yield | 10-15 ft minimum |
| Normal yield | 15-25 ft |
| Low yield | 25-50+ ft |
| Seasonal variation | Add extra for buffer |
Rod Units vs. Drop Pipes
Drop Pipe Kits Include
- 1" Schedule 80 PVC pipe
- Stainless steel coupler
- Connects pump head to cylinder
Lift Rod Assemblies
- Fiberglass rods
- Connect pump mechanism to piston
- Same quantity as drop pipes
Note: Drop pipe and lift rod quantities match - each drop pipe kit pairs with a lift rod assembly.
Top Drop Pipe Kit
The uppermost drop pipe has special features:
Weep Hole
- Pre-drilled drain hole
- Provides freeze protection
- Water drains below frost line
Weep Hole Depth
- Standard: Based on regional frost line
- Custom: Specify your local frost depth
We Calculate for You
When you request a quote:
- Provide static water level
- Provide total well depth
- We calculate exact configuration
- Optimal drop pipe combination specified
Don't Guess
Why Accuracy Matters
- Too short = pump air, no water
- Too long = hit well bottom
- Right length = optimal performance
We Help
Our quotes include exactly what you need:
- Correct quantity of each length
- Proper top drop pipe
- Matched rod assemblies