12.3 Dilution Procedures and Measuring Concentrates

Quick Answer: Dilution is 40 CFR 171.103(c)(5)(vi). In New Jersey you also measure the concentrate, protect the water supply under N.J.A.C. 7:30-10.2(h), keep mix out of food and drink containers under 7:30-9.6(c), and record the recipe under 7:30-6.8: total concentrate, total diluent, and total mixture used.

Wrong dilution is not a rounding error. Too strong is a label, residue, phytotoxicity, and exposure violation. Too weak is ineffective use and a resistance pressure under (c)(5)(v). N.J.A.C. 7:30-10.2(a) still forbids use inconsistent with the registered label. The closed-book Core will give you a percent solution or a rate in ounces per gallon and expect the arithmetic, the container rule, the backflow rule, and the record.

Read the rate before you measure

Keep a readable copy of the registered label at the mixing site — N.J.A.C. 7:30-10.2(i). Find the rate that matches this site, this pest, this equipment, and this formulation. Common expressions:

• Fluid ounces of concentrate per gallon of finished spray.
• Pints or quarts per 100 gallons.
• Pints per acre in a stated gallons-per-acre (GPA) band.
• Percent solution (usually volume/volume for liquids).
• Packets or ounces by weight for WP and DF.

Do not convert a WP as if it were an EC unless the label gives that conversion. Do not use a percent solution when the label gives only a per-acre rate. Do not “match the color” of last week’s tank. RTU products are already diluted; adding water or adding more concentrate changes a finished, labeled mixture.

Put on mix/load PPE before the seal breaks. Measure with dedicated graduated cylinders, measuring cups, or scales that live in the pesticide operation — not a kitchen cup, not a soda-bottle cap, not “about a glug.”

Percent solutions and ounces per gallon

One U.S. gallon is 128 fluid ounces. A 1% volume/volume finished spray contains 1.28 fluid ounces of liquid concentrate per gallon of mixture (0.01 × 128). Field cards sometimes round that to 1.3 ounces; PACER math is cleaner if you keep 1.28 and multiply.

Worked example 1 — four gallons of a 1% solution

A Category 7A applicator in Trenton must mix 4 gallons of a 1% finished spray. The EC label allows that 1% solution for indoor crack-and-crevice on the listed pest.

• Concentrate: 4 × 1.28 fl oz/gal = 5.12 fl oz of EC.
• Diluent (water): 4 gallons minus 5.12/128 gallons = 4 − 0.04 = 3.96 gallons of water.
• Total mixture: 4 gallons.

N.J.A.C. 7:30-6.8 recipe for that batch: total concentrate 5.12 fl oz; total diluent 3.96 gallons. If the applicator uses the entire batch on that apartment, total mixture used is 4 gallons. If half is left in the tank and later applied at another unit the same day, each individual application gets its own mixture-used entry; the recipe still describes how the tank was mixed.

Worked example 2 — label rate in gallons, not a percent

A Category 3B turf herbicide label says 1.5 pints of product per acre in 20 to 40 gallons of water per acre. A crew in Monmouth County will treat 0.50 acre with a 15-gallon tank.

• Concentrate: 1.5 pints/acre × 0.50 acre = 0.75 pint = 12 fl oz (because 1 pint = 16 fl oz).
• Spray volume: 15 gallons on 0.50 acre = 30 GPA, which sits inside the labeled 20–40 GPA band.
• Diluent: the water needed to bring the tank to that 15-gallon mixture (15 gallons minus the 0.75 pint of concentrate).
• Treated area to record: 0.50 acre, because the label specified a rate per given area (7:30-6.8(a)5i).

Do not “make it 1%” because the 7A example used 1%. This label never asked for a percent solution. Inventing one would over- or under-apply the per-acre rate.

Fill sequence that keeps both examples legal:

1. Readable label on the pad (10.2(i)).
2. Mix/load PPE on.
3. Start with clean water through a hose that has an effective backflow device (10.2(h)); an air gap above the tank rim is one effective method.
4. Add about half the water, start agitation if the formulation needs it (WP, DF, many F/SC).
5. Measure concentrate in a dedicated device; add it; rinse the measuring device into the tank if the label allows.
6. Finish filling to the target volume; leave headspace; agitate.
7. Write the recipe.

Measuring concentrates without food or drink containers

N.J.A.C. 7:30-9.6(c) is absolute: no person shall place or keep any pesticide in any container commonly used for food, drink, or household products. Leftover 1% mix in a sports-drink bottle, concentrate in a milk jug, or granules in a coffee can is a violation whether or not a child drinks it. Dedicated measuring cups that resemble kitchen ware should be marked as pesticide-only and stored with the pesticides, never returned to a kitchen.

Keep product in the original labeled container when you can. If you transfer to a service container, 7:30-9.6(b) requires either a copy of the registered label or a readable label with:

1. Brand or trade name
2. EPA Registration Number
3. Name and percentage of active ingredients
4. Signal word: Danger-Poison, Warning, or Caution

7:30-9.6(a) forbids storing, transporting, or possessing pesticide if the registered label is missing, obscured, altered, or unreadable, with listed exceptions that include service containers and application equipment. Application equipment that holds mix is not an excuse to skip identification of what is in the tank. 7:30-9.6(d) still requires compliance with federal container and containment rules in 40 CFR Parts 156 and 165.

Measure WP and DF on a scale when the label is in ounces by weight. A “level cup” of two different dry products is not the same dose. Make a slurry for many WPs before they go into the tank, as the label directs, so they do not clump.

Fill water without back-siphoning

N.J.A.C. 7:30-10.2(h): no person shall add water to any pesticide handling, storage, or application equipment via a hose, pump, or other equipment unless that hose, pump, or other equipment is fitted with an effective valve or device to prevent backflow of pesticides or liquids containing pesticides into water-supply systems, streams, lakes, other sources of water, or other areas.

The illegal picture is a garden hose submerged in a spray tank at a hydrant, barn spigot, or hose-bib with no air gap, vacuum breaker, check valve, or reduced-pressure device. If pressure drops, tank contents can siphon into drinking water. Effective protection includes an air gap above the flood rim, a hose-bib vacuum breaker, a reduced-pressure zone assembly, or another device that actually prevents backflow. The rule is not limited to restricted-use products, chemigation, or public hydrants. Filling from a pond or stream with the hose in the tank is the same problem aimed at surface water.

Do not use the mix-pad water source for decontamination or eyewash unless valves or an air gap keep pesticide out of that water. WPS agricultural sites spell that out in 40 CFR 170; New Jersey 7:30-10.2(h) already covers the fill hose for every commercial mix.

Record the recipe, not just the product name

N.J.A.C. 7:30-6.8(a)4 requires the “recipe” used to mix the pesticide as required by the label. The recipe shall consist of:

• the total amount of pesticide concentrate; and
• the total amount of diluent.

7:30-6.8(a)5 then requires the total amount of pesticide mixture used for each individual application, and the size of the area treated when a rate per given area is specified on the label. Brand name, active ingredients, and EPA registration numbers are separate required fields. Writing “1% mix” or “per label” is not a recipe. Writing only the gallons sprayed, without concentrate and diluent, is not a recipe.

Write the record no later than 24 hours. Keep commercial application records 3 years (5 years for termiticides). The record must be immediately available to NJDEP and to emergency medical personnel. A customer gets a copy on written request. Aquatic applications use the 7:30-9.3(j) record instead of 6.8, but land-based Core candidates still learn the 6.8 recipe.

If you mix 25 gallons and apply 10 gallons at the first property and 15 at the second, the recipe (concentrate + diluent for that 25-gallon batch) can be recorded for the mix; mixture used is 10 gallons at site one and 15 gallons at site two, each with place, date, applicator name and license number, and treated-area size when the label is a per-area rate. Do not invent a new percent at the second stop to “stretch” leftover mix. Apply leftover mix only to a labeled site at a labeled rate, or handle it as unused pesticide — never as a drink-bottle leftover.

Worked New Jersey scenario — putting the pieces on one pad

A 3B crew in Cherry Hill mixes a labeled liquid herbicide at 2 fl oz concentrate per gallon of finished spray in a 25-gallon tank.

• Concentrate: 25 × 2 = 50 fl oz (0.39 gallon).
• Diluent: 24.61 gallons of water, filled through a hose with a vacuum breaker kept above the tank rim (7:30-10.2(h)).
• Recipe on the 6.8 record: concentrate 50 fl oz; diluent 24.61 gal.
• They spray 20 gallons on 8,000 square feet of labeled turf. Mixture used: 20 gallons; size of treated area: 8,000 sq ft (label had a rate per area).
• Five gallons remain. They do not pour it into a Gatorade bottle (7:30-9.6(c)). They apply it the same day to another labeled turf site at the same rate, or keep it in the tank or a properly labeled service container (7:30-9.6(b)).
• The measuring cylinder stays in the pesticide lockup, not under the coffee maker.

High-yield traps

• 1% v/v = 1.28 fl oz per gallon, not 1 ounce and not 1 cup.
• Per-acre rates are not percent solutions unless the label says so.
• Recipe = concentrate + diluent; mixture used is a separate number.
• “Per label” is not a 6.8 recipe.
• Food, drink, and household bottles are forbidden even for dilute leftover mix.
• Submerged fill hoses without an effective backflow device violate 10.2(h) even if no siphon is seen.
• The registered label must be readable at the mix site (10.2(i)).

Official resources

• 40 CFR 171.103(c)(5)(vi) dilution procedures
• N.J.A.C. 7:30-6.8 records
• N.J.A.C. 7:30-9.6 containers and container labeling
• N.J.A.C. 7:30-10.2 pesticide use and/or application