2.10 The Colorado Chemigation Act and Backflow Prevention

2.10 The Colorado Chemigation Act and Backflow Prevention

A separate statute. Everything else in this chapter comes from the Pesticide Applicators' Act (Title 35, Article 10). Chemigation has its own act — the Colorado Chemigation Act, C.R.S. Title 35, Article 11 — with its own rules at 8 CCR 1203-8, its own permit, its own inspection program, and its own penalty. Citing Article 10 for a chemigation question is a wrong answer.

Chemigation is the application of a chemical — meaning any fertilizer or pesticide — to land or crops with water by means of a closed irrigation system. It is most common on agricultural land, but it also occurs on turf and in greenhouses. The purpose of regulating it is narrow and specific: preventing contamination of groundwater by setting standards for the installation and maintenance of anti-siphoning devices. The Department carries out the program in conjunction with groundwater management districts.

---

1. Who Needs a Permit, and When It Expires

You need a chemigation permit if you have any of the following:

• one well — one injection site
• one well — multiple injection sites
• multiple wells — one injection site

To obtain one: complete the chemigation permit application, certify that the irrigation system meets all standards, and pay the permit fee. Permits are good for one year and expire on March 31 of each year.

┌─────────────────────────────────────────────────────────────────────────────┐
│  PERMIT YEAR:  April 1 ─────────────────────────────────────► March 31      │
│                                                                             │
│  Renewal is annual. The expiration is a FIXED CALENDAR DATE, not an         │
│  anniversary of issuance — unlike an individual applicator license, whose    │
│  anniversary is the licensee's birth date under 8 CCR 1203-2 Part 2.41.     │
└─────────────────────────────────────────────────────────────────────────────┘

---

2. The Required Mechanical Devices (8 CCR 1203-8 Part 6)

Any irrigation distribution system used for chemigation, except open discharge systems, must be equipped with the devices below, permanently installed in accordance with the manufacturer's specifications and at the location the manufacturer specifies.

[!WARNING] Do not quote a cracking pressure for the injection line check valve. An earlier version of 8 CCR 1203-8 required a minimum opening (cracking) pressure of 20 psi, and that provision — old Rule 6.12 — has been repealed. The current rule specifies chemically resistant construction and the two directions of flow it must block, with no psi figure at all. Any study source stating "10 psi under 8 CCR 1203-8" is simply wrong; sources citing 20 psi are quoting a repealed rule. Individual pesticide labels may still impose their own chemigation hardware conditions, and those remain enforceable as labeling.

Replacement pipeline check valves must meet stated minimums (Part 6.15): corrosion-resistant body and components; a sealing mechanism that closes prior to or at the moment water ceases to flow downstream, either diaphragm-actuated by hydraulic line pressure, spring loaded, or weight loaded, providing a watertight seal against reverse flow; moving components designed to prevent binding, distortion, or misalignment; and a design allowing repair and maintenance including removal from the pipeline. All required equipment must be maintained in working condition and repaired to its originally designed condition (Part 6.16).

---

3. The Inspection Process

The chemigation inspection is a scheduled, cooperative process — not a surprise audit:

1. An irrigation system may be inspected once every two years.
2. You are notified of the time and date of the inspection.
3. You are entitled to be present at the inspection.
4. You are billed for an inspection fee, which must be paid within 45 days of the inspection.
5. If you refuse access, an inspection warrant can be issued and the system inspected.
6. Any irrigation system without a permit can be inspected if there is reasonable cause to suspect a violation of the Chemigation Act.
7. Many groundwater management districts work with CDA to carry out inspections and enforce the Act.

---

4. Penalty

C.R.S. § 35-11-115(1): any person utilizing chemigation without a permit commits a class 6 felony, punishable as provided in § 18-1.3-401(1)(a)(IV) and by a fine not to exceed one thousand dollars.

That is a materially different exposure from the Pesticide Applicators' Act, where the criminal provisions in § 35-10-123 create class 2 misdemeanors and the civil ceiling in § 35-10-122 is $2,500 per violation (doubled for a repeat). If a question offers "class 2 misdemeanor" for unpermitted chemigation, it has swapped the two statutes.

---

5. Why Backflow Happens

Understanding the physics makes the device list memorable rather than arbitrary.

• Back-siphonage occurs when pressure in the supply line drops below atmospheric — most commonly when the irrigation pump shuts down, a main breaks, or a large draw occurs downstream. The chemical-laden water in the pipeline is then pulled backward toward the well. Devices 1, 2, and 4 exist for this failure mode: the check valve blocks the reverse flow, the vacuum relief valve breaks the siphon by admitting air, and the low-pressure drain dumps whatever leaks past the check valve twenty feet downslope, away from the casing.
• Backpressure and gravity flow run the other direction: irrigation water under operating pressure forces its way up the injection line into the chemical tank, or the elevated chemical tank simply drains into the pipeline when everything is off. Device 5 blocks both.
• Continued injection into a stopped pipeline is the third failure. Without device 6, an injection pump keeps metering concentrate into a static pipe, producing a concentrated slug that drains straight back toward the source. The interlock is the only device that addresses this one.

Compare this with tank filling on a mixing pad, where the accepted safeguards are a physical air gap or a reduced pressure zone (RPZ) backflow preventer. The chemigation rule addresses a permanently plumbed system, so it requires permanently installed hardware and an annual permit rather than an operator practice.