Should you use salt, sand, or the liquid the state trucks spray? Each one does a different job. Rock salt melts ice, but it stalls below about 15°F. Sand doesn’t melt anything; it only adds grip. Salt brine is sprayed before a storm so snow and ice can’t bond to the pavement in the first place. The best winter plans use the right one for the pavement temperature, and plow first every time.
Here’s how they compare, based on guidance from the NH Department of Environmental Services (NHDES) and UNH’s Green SnowPro training.
Rock Salt: The Workhorse, With a Temperature Limit
Rock salt (sodium chloride) is the most common de-icer in New Hampshire because it’s cheap, easy to store and easy to spread. It works by mixing with moisture to form a brine, which lowers the freezing point and loosens the bond between ice and pavement.
The catch is temperature. NHDES says sodium chloride loses its effectiveness below 15°F, and that applying it below that point, even at high rates, won’t produce significant melting. Green SnowPro training materials show how fast the drop-off is. One pound of salt melts about 46 pounds of ice in 5 minutes at 30°F, but only about 6 pounds in an hour at 15°F. Below that, it’s rated ineffective.
That matters in Concord. In NOAA daily records for the Concord area from 1991 to 2020, the overnight low dropped below 15°F on an average of about 17 nights in January, 14 in February and 10 in December. On those mornings, throwing more salt at a lot mostly wastes salt.
Two more rules from the state’s guidance: go by pavement temperature, not air temperature, and plow first. Salt is for breaking the bond between ice and pavement, not for burning off snow.
Sand: Traction Only, and It Doesn’t Go Away
Sand gives tires and boots something to grip. It doesn’t melt ice, and once new snow buries it, it stops helping.
Green SnowPro training is blunt about sand. It’s generally not recommended above 15°F, it has to be cleaned up, and even after cleanup, 50 to 90 percent of it stays in the environment, where it clogs catch basins, culverts and drainage ditches and washes into streams. NHDES’s parking lot rate guidance reserves sand mainly for very cold conditions and freezing rain, spot-treating hazardous areas like ramps, steps and loading docks. It also tracks inside and leaves a spring cleanup bill.
Salt Brine: Stop the Ice Before It Sticks
Brine is just salt dissolved in water, mixed to about 23.3 percent salt, the concentration with the lowest freezing point. Sprayed on dry pavement before a storm, it acts like non-stick spray in a pan. Snow lands on a treated surface, never bonds, and plows off clean.
According to NHDES’s anti-icing best management practices:
- Brine works best applied 1 to 2 hours before precipitation, and can go down up to 24 hours ahead.
- Typical rates are about 0.5 to 0.75 gallons per 1,000 square feet.
- Anti-icing costs roughly 50 percent less than reactive de-icing.
- It’s not advised before freezing rain, which can dilute it and refreeze.
Brine also makes rock salt work better. “Pre-wetting” salt with brine jump-starts melting and cuts the bounce and scatter that throws dry salt into the grass, and the state’s guidance says it typically lets applicators cut rates by 15 to 20 percent.
Quick Comparison
| Rock salt | Sand | Salt brine | |
|---|---|---|---|
| What it does | Melts and loosens ice | Adds traction only | Prevents snow and ice from bonding |
| When it works best | Pavement about 15°F and up | Very cold snaps, freezing rain, spot hazards | Before the storm, roughly 15–35°F pavement |
| Main downside | Chloride runoff; stalls when it’s colder | Clogs drains, tracks inside, needs cleanup | Needs spray equipment and good timing |
Why Over-Salting Is a New Hampshire Problem
More salt isn’t safer, just costlier. NHDES reports more than 50 New Hampshire waterbodies are impaired for chloride, and chloride doesn’t break down, so nearly all salt spread on pavement ends up in surface water or groundwater. In four chloride-impaired watersheds along the southern I-93 corridor, NHDES found 45 to 50 percent of the road-salt load came from private roads and parking lots, more than state or town roads.
That’s why NHDES runs Green SnowPro, a certification program for commercial salt applicators. Under RSA 508:22, certified applicators and the property owners who hire them get limited liability protection for snow and ice conditions when program requirements are met. Ask any contractor whether they’re certified and whether their spreaders are calibrated.
Salt is also hard on lawn edges, shrubs and concrete. If your property has pavers and walkways or retaining walls near treated areas, keep piles off them and check joints and edges in spring.
A Simple Plan for Your Lot or Driveway
- Plow early and often so snow doesn’t pack down.
- Anti-ice with brine before forecast snow when pavement is in the workable range, but not before freezing rain.
- Use salt after plowing, and less as pavement warms. Pre-wet it if your contractor can.
- Save sand for deep cold and spot hazards like steps, ramps and loading docks.
- Pick a snow storage spot where melt won’t drain back across the lot and refreeze. See when snow starts in Concord for the timeline.
- Finish leaf cleanup so wet leaves don’t freeze into slick mats. Our fall cleanup guide covers it.
Winter Ice Control From Globe Green
Globe Green LLC is based at 90 Airport Rd in Concord. Our snow removal service covers plowing, salting and sidewalk clearing for commercial lots, HOAs and other large properties around the Concord area, and we plow residential driveways in Concord. To get on a route before the first storm, contact us or call (603) 420-7771.
Frequently Asked Questions
Is salt or sand better for an icy driveway or parking lot?
Salt is better when the pavement is about 15°F or warmer, because it melts ice and loosens it from the surface. Sand only adds traction, so it’s mainly useful in deep cold or for spot-treating steps and ramps.
At what temperature does rock salt stop working?
NHDES says rock salt (sodium chloride) loses its effectiveness below about 15°F. Below that, even heavy applications won’t melt much ice, so plowing, sand for traction or a colder-rated blend is the better choice.
What is salt brine, and why do trucks spray it before storms?
Salt brine is salt dissolved in water at about 23.3 percent. Sprayed on pavement 1 to 2 hours before a storm, it keeps snow and ice from bonding, so plows scrape clean with less salt afterward.
Does salt hurt pavers and retaining walls?
Salt and repeated freeze-thaw are hard on hardscape joints and on nearby plants and lawn edges. Keep plow piles and heavy salt off pavers and walls, and inspect joints and edges in spring.
What is a Green SnowPro certified contractor?
Green SnowPro is NHDES’s training and certification program for commercial salt applicators, focused on calibrated, lower-salt ice control. Under RSA 508:22, certified applicators and the property owners who hire them get limited liability protection for snow and ice conditions when program requirements are met.
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