Bringing a lawn sprinkler system back to life after a Colorado winter requires careful timing. The process involves navigating two challenges: the unpredictable nature of spring weather, which threatens costly damage from freezing temperatures, and mandatory water conservation rules enforced by local providers. Understanding the balance between weather readiness and municipal regulations is key to safely transitioning your irrigation system from winterized storage to active use.
Determining the Optimal Start Time
The decision to activate your sprinkler system should be driven primarily by the risk of a hard freeze. Water expands when it freezes, and even a single night below 32°F can cause pipes, valves, and the backflow prevention device to crack, leading to expensive repairs. This risk is high in Colorado, where late-season snow and overnight freezes are common well into the spring.
While the average last freeze date for many areas along the Front Range is around May 5th, freezing temperatures have historically occurred as late as mid-May. It is best to wait until the threat of consecutive overnight temperatures below freezing has consistently passed. Premature activation forces you to repeatedly drain and restart the system, or risk a burst pipe.
Soil temperature is another factor to monitor, as the ground needs to be thawed deep enough to accommodate the water. Even if air temperatures are warm, the soil may hold residual frost, particularly in shaded sections. The safest window for initial startup generally falls between late April and the middle of May, depending on your elevation. During warm, dry spells before this window, it is safer to hand-water trees and stressed lawn areas rather than activating the entire system.
Navigating Regional Water Restrictions
Even after the weather has stabilized, your ability to run the sprinklers is governed by the conservation rules of your local water provider. Many Colorado municipalities operate under permanent or seasonal mandatory watering schedules designed to conserve limited water resources. These regulations often dictate the number of watering days per week and the permissible hours of operation.
You must check your specific provider’s website for current restrictions, as these rules are subject to change based on drought conditions and reservoir levels. A common restriction prohibits watering between 10 a.m. and 6 p.m., when high temperatures cause excessive evaporation. Most residential areas are limited to watering a maximum of two or three days per week.
These rules are enforceable ordinances that carry fines for non-compliance, such as allowing water to pool in the street or spray onto concrete. If you have recently installed new sod or seed, you may need to apply for a temporary variance permit for the more frequent watering necessary for establishment. Adhering to these local guidelines ensures responsible water use and avoids penalties.
Safe System Activation Process
The mechanical process of turning on your irrigation system must be executed slowly to prevent a damaging pressure surge, commonly known as a water hammer. Before allowing water to enter the system, confirm that all drain and bleeder valves, opened for winterization, are now closed. Inspect the above-ground backflow prevention device for visible cracks or damage from winter freezing.
The main shut-off valve, often located in the basement or a utility area, should be opened very gradually, performing only a quarter-turn at a time. This slow introduction of water allows the empty pipes to fill without a sudden rush of pressure that could rupture fittings. Wait 30 to 60 seconds after the initial quarter-turn to allow pressure to equalize throughout the main lines before opening the valve further.
Once the main valve is fully open, pressurize the backflow preventer, following the specific sequence of its valves if applicable. Finally, manually run each zone from the controller for a few minutes while walking the property. This test run allows you to identify any broken sprinkler heads, clogged nozzles, or leaks that must be repaired quickly to comply with water waste ordinances.
Setting Up Your Initial Watering Schedule
After activating the system and confirming it is free of leaks, the initial watering schedule should prioritize conservation and deep root development. Avoid watering daily, as frequent, shallow watering encourages grass roots to stay near the surface, making the lawn less tolerant of heat and drought. Focus on watering deeply and infrequently.
Colorado’s soils are often clay-heavy, meaning water is absorbed slowly and is prone to running off before it can soak in. To counteract this, employ the “cycle and soak” method. This method splits the total watering time for a zone into two or three shorter segments with a rest period in between. For example, instead of running a zone for a single 15-minute cycle, program it for three 5-minute cycles, with a 30-to-60-minute soak time between segments to allow the water to penetrate the soil.
In the cooler spring months, one to two watering days per week is sufficient to maintain a healthy lawn. As the season progresses and temperatures increase, gradually increase the duration or frequency. Always adjust based on the visual needs of the grass, not merely on the calendar. This practice ensures water reaches the necessary root zone without being wasted to evaporation or runoff.