DIY Winter Protection That Actually Works—And Costs Only 7¢ Per Gallon

If you're winterizing portable sanitation equipment, brine solution is one of the most effective, inexpensive, and reliable methods available. Unlike salt alone, properly mixed brine has a proven freeze point and can be stored for up to a year. Here's how to make it—and why experienced operators prefer it.

What Is Brine and Why Use It?

Brine is simply a salt-water mixture. When properly balanced, 23% salt brine achieves the lowest freeze point possible: approximately 0°F. This makes it ideal for fresh water tank winterization in portable sanitation operations.

Why Choose Brine Over Other Options?

• Inexpensive—costs only 7¢ per gallon after equipment setup
• Proven freeze protection—achieves 0°F freeze point
• Can be stored for up to a year
• Consistent results when properly mixed
• Can be used multiple ways (direct application, pre-wetting, pre-treating)
• Simple two-ingredient formula (salt + water)
• Minimal equipment required

Equipment You'll Need

Brine making requires only four basic pieces of equipment:

1. Mixing Tank
• Open-top tank (easily accessible for adding salt)
• Size: Depends on your volume needs
• Should allow easy overflow into holding tank
• Typically 100-500 gallons depending on operation size

2. Holding Tank
• Storage for finished brine solution
• Must be separate from mixing tank
• Can be stored outdoors (if temps stay above 0°F)
• Recommended: Store indoors to eliminate freezing risk

3. Small Pump
• Used to circulate and transfer brine
• Helps with water distribution during mixing
• Optional but recommended for larger operations
• Prevents settling and maintains consistency

4. Salimeter or Hydrometer
• Measures salt concentration in solution
• Critical for quality control
• Two measurement types: - Hydrometer: Reads 1.176 when correct
- Salimeter: Reads 23% when correct
• Cost: $20-$40, essential investment

Step-by-Step: How to Make 23% Brine Solution

Step 1: Calculate Your Batch Size

Decide how much brine you need. Example: Let's make 100 gallons of 23% brine.

Formula: 2.5 lbs salt per gallon of water

For 100 gallons: 100 gallons × 2.5 lbs = 250 lbs of salt needed

Step 2: Add Salt to Mixing Tank

• Pour approximately 250 lbs of salt into your open-top mixing tank
• Make sure tank opening is large enough for easy salt addition
• Rock salt or calcium chloride both work (rock salt is cheaper)
• Don't worry about small salt clumps—they'll dissolve

Step 3: Add Water Slowly From the Bottom

This is critical for proper mixing:

• Position water intake at the BOTTOM of the mixing tank
• Add water slowly and allow it to percolate UP through the salt
• This upward flow dissolves salt evenly
• Water will overflow into your holding tank
• Continue until all water is added (100 gallons in our example)

Why from the bottom? Bottom-up water addition distributes salt evenly and prevents salt from clumping on top.

Step 4: Check Concentration (Quality Control)

This is the most important step—don't skip it!

• Float a hydrometer or salimeter directly in your holding tank
• Read the value at the water surface
• Target reading: 1.176 (hydrometer) OR 23% (salimeter)

If concentration is too low:
• Pump some brine from holding tank back into mixing tank
• Allow excess to overflow
• This concentrates the remaining solution
• Re-test until you reach 1.176 or 23%

If concentration is too high:
• Simply add fresh water to holding tank
• Stir well and re-test
• Adjust until perfect

Critical Information: Freeze Points at Different Concentrations

Don't guess your salt concentration! Here's why:

• 10% salt solution freezes at approximately 28°F
• 15% salt solution freezes at approximately 15°F
• 20% salt solution freezes at approximately 5°F
• 23% salt solution freezes at approximately 0°F (lowest possible)
• Above 23%: No additional freeze protection benefit

Using a hydrometer or salimeter ensures you're getting your money's worth.

Storage and Maintenance

How Long Does Brine Last?
Properly made brine can be stored for up to one year without degradation.

Storage Conditions:
• 23% brine may be stored outside if temps stay above 0°F
• Recommended: Store indoors to eliminate freezing risk
• If stored outdoors in extreme cold: Use a circulator pump to prevent stratification and freezing
• Keep records: Note date created, who mixed it, and final concentration
• Retest concentration before using old batches (especially after long storage)

Cost Analysis: Why Brine Is Smart Economics

At $58 per ton for salt, brine costs approximately 7¢ per gallon after equipment setup. Compare this to:

• Premixed antifreeze: $2-5 per gallon
• Calcium chloride: $1-2 per gallon
• Methanol: $1-3 per gallon

Over a winter season with multiple tanks and vehicles, brine saves thousands of dollars while providing superior freeze protection.

Multiple Uses for Your Brine

Once made, brine can be used in three ways:

1. Direct Application
Add brine directly to fresh water tanks for freeze protection

2. Pre-Wetting Salt
Use brine to pre-wet road salt or granular de-icer before applying

3. Pre-Treatment
Pre-treat salt loads before loading into application vehicles

Quality Control and Documentation

Professional operations maintain records:

• Date batch was created
• Who mixed and checked the batch
• Final concentration reading (hydrometer or salimeter value)
• Keep records for at least 2 years
• This protects your company in case of disputes

Practical Tips from Highway Departments

These best practices come from NH DOT and other transportation agencies that have perfected brine operations:

✓ Use a circulator pump if storing outdoors in extreme cold—prevents stratification
✓ Retest brine concentration before each use—especially older batches
✓ Keep detailed records of each batch created
✓ Clean your salimeter/hydrometer between uses to ensure accuracy
✓ Mix in bulk—economies of scale reduce per-gallon cost
✓ Store indoors when possible—eliminates freezing risk entirely

Common Mistakes to Avoid

❌ Not measuring salt concentration—you might think you have 23% protection when you only have 15%
❌ Adding water from the top—causes uneven mixing and salt clumping
❌ Skipping quality control steps—costs more money than it saves
❌ Using old brine without retesting—concentration can change during storage
❌ Not keeping records—can't verify batch quality if problems arise
❌ Storing in extreme cold without circulation—brine can freeze even at 23%

When to Use Brine for Portable Sanitation

Brine solution works best for:

• Fresh water tank winterization
• Operations in climates where temps drop to 0°F or below
• Long-term storage (up to one year)
• Cost-conscious operators managing multiple units
• Areas with extreme seasonal variation

The Bottom Line

Making brine solution is simple, inexpensive, and proven to work. At 7¢ per gallon, it's the most cost-effective freeze protection available. The key is proper mixing (salt from bottom, water from bottom), accurate concentration testing (1.176 or 23%), and good record-keeping.

Start preparing your brine NOW—don't wait until January when you need it urgently. Make your batch in fall, test it thoroughly, and you'll have reliable freeze protection all winter long.

Get the Equipment You Need

TOICO supplies hydrometers, salimeters, and brine-making equipment designed for portable sanitation operations. We can help you set up your brine operation efficiently and cost-effectively.

Whether you choose brine, antifreeze, or tank heaters, the key is planning ahead. Contact TOICO at 1-888-935-1133 or visit www.toico.com to discuss winterization strategies for your operation.

Don't let winter catch you unprepared. Make brine now. Test it thoroughly. Protect your equipment. Keep operating all season long.