A comprehensive guide to keeping your irrigation system running efficiently in Colorado’s unique climate. This guide is based on over 15 years of experience servicing thousands of irrigation systems across the Denver metro area.
Understanding Denver’s Irrigation Challenges
Denver’s semi-arid climate and dramatic temperature swings create specific challenges for irrigation systems that homeowners in other regions don’t face.
Climate Factors Affecting Your System
Low Humidity: Denver’s average humidity of 30-40% means water evaporates quickly. Proper head adjustment and watering schedules are critical to ensure water reaches roots before evaporating.
Intense Sun: At 5,280 feet elevation, UV radiation is more intense, which can degrade exposed plastic components faster than at sea level.
Temperature Extremes: Denver regularly experiences 50+ degree temperature swings in a single day during spring and fall. These fluctuations stress pipes and fittings.
Clay Soils: Much of the Front Range has heavy clay soil that absorbs water slowly. Watering too fast results in runoff; proper scheduling uses multiple short cycles.
Freeze-Thaw Cycles: Denver can experience freezing temperatures as early as September and as late as May. Water left in pipes can freeze, expand, and crack components.
Seasonal Maintenance Calendar
Spring (March - May)
Before Startup
- Inspect valve boxes for winter damage or debris
- Check exposed pipes and backflow preventers for visible cracks
- Verify the main shutoff valve operates smoothly
- Clear debris from sprinkler heads
- Review controller programming and battery backup
During Startup
- Turn on water slowly to prevent pressure surges
- Run each zone and check for proper head operation
- Look for heads that don’t pop up, spray incorrectly, or leak
- Check for soggy areas indicating underground leaks
- Verify backflow preventer operation
- Adjust head positions knocked askew by winter
After Startup
- Set appropriate watering schedule for spring conditions
- Monitor the first few weeks for developing leaks
- Document any issues for future reference
Summer (June - August)
Weekly Tasks
- Visually inspect system during watering cycles
- Check for clogged or misaligned heads
- Adjust watering schedule based on weather and lawn condition
- Monitor water bills for unexpected increases (leak indicator)
Monthly Tasks
- Inspect valve boxes for standing water or leaks
- Check backflow preventer for proper operation
- Clear debris from filter screens if applicable
- Verify rain sensor operation (if equipped)
Summer Watering Tips
- Water early morning (4-6 AM) to minimize evaporation
- Use cycle-and-soak for clay soils (two 10-minute cycles instead of one 20-minute cycle)
- Adjust for rainfall—most established lawns need about 1 inch of water per week total
- Deep, infrequent watering promotes deeper root growth
Fall (September - November)
Early Fall
- Reduce watering frequency as temperatures cool
- Inspect and repair any damage from summer
- Consider aeration and overseeding
- Check controller clock for daylight saving time changes
Before Winterization
- Schedule blowout service before freezing temperatures arrive
- Document any issues to address next spring
- Note head positions that need adjustment
Winterization (Blowout)
- Professional blowout with compressed air removes water from all lines
- Backflow preventer should be drained and protected
- Controller should be turned off or set to rain mode
- Main water supply to the system should be shut off
Winter (December - February)
Periodic Checks
- After major temperature swings, visually inspect exposed components
- Ensure backflow preventer remains properly drained
- Keep valve boxes clear of snow and ice for drainage
Common Denver Sprinkler Problems and Solutions
Problem: Heads Not Popping Up
Symptoms: One or more heads fail to rise when the zone runs.
Common Causes:
- Debris clogging the head mechanism
- Head buried by grass growth or soil settling
- Low water pressure in that zone
- Damaged head internals from grit accumulation
Solutions:
- Clean debris from around the head
- Raise buried heads to soil level
- Check for upstream leaks reducing pressure
- Replace heads showing wear
Prevention: Keep heads trimmed and clear, replace heads showing wear before they fail.
Problem: Water Continues After Zone Shuts Off
Symptoms: Sprinkler heads continue dripping or flowing after the controller turns off the zone.
Common Causes:
- Debris in valve diaphragm preventing closure
- Worn diaphragm
- Damaged solenoid
- Cracked valve body
Solutions:
- Disassemble and clean valve diaphragm
- Replace diaphragm if worn
- Replace solenoid
- Replace entire valve if body is damaged
Prevention: Install filters to prevent debris, schedule annual valve inspection.
Problem: One Zone Has Low Pressure
Symptoms: A single zone has weak spray while others work normally.
Common Causes:
- Partially closed valve
- Debris restricting flow
- Leak in that zone’s lateral lines
- Too many heads on one zone
Solutions:
- Check valve is fully open
- Clean valve and filter
- Inspect for leaks when zone is running
- Consider splitting zone if too many heads
Problem: High Water Bill with No Visible Leak
Symptoms: Water usage increases significantly without obvious cause.
Common Causes:
- Underground mainline leak
- Valve stuck partially open
- Controller programming error
- Running more frequently than intended
Solutions:
- Schedule leak detection service
- Check all valves with water off (no heads should be weeping)
- Review controller programming
- Check for manual watering you may have forgotten about
Problem: Controller Skipping Zones
Symptoms: Some zones don’t run even though programmed.
Common Causes:
- Faulty wiring connection
- Cut or damaged wire
- Faulty solenoid
- Controller zone output failure
Solutions:
- Check wire connections at controller and valve
- Test for wire breaks (professional wire locator may be needed)
- Test solenoid with multimeter
- Test different zone on controller to isolate issue
Denver Water Restrictions and Compliance
Current Watering Rules
Denver Water and most Front Range water providers have watering restrictions during summer months. Typical restrictions include:
- Watering Days: Usually limited to specific days based on address
- Watering Hours: Typically prohibited during midday hours (often 10 AM - 6 PM)
- Duration Limits: May limit continuous watering time per zone
Important: Rules vary by water provider and may change annually. Always verify current restrictions with your specific water provider:
Smart Watering Practices
Even without restrictions, following these practices conserves water and money:
- Water early morning when evaporation is lowest
- Use cycle-and-soak to prevent runoff on clay soils
- Adjust schedules monthly based on actual weather conditions
- Install a rain sensor to prevent watering during and after rainfall
- Consider smart controllers that adjust automatically based on weather data
Neighborhood-Specific Considerations
Cherry Creek & Wash Park
Older systems (20+ years) often have thin-wall PVC mainlines that become brittle. Consider proactive replacement before catastrophic failure. Mature trees may require adjusted watering zones.
Highlands Ranch & Centennial
Newer developments may have builder-grade components. Upgrade to commercial-grade heads in high-traffic areas. HOA watering requirements may necessitate smart controller installation.
Lakewood & Arvada
Heavy clay soils require cycle-and-soak watering. Consider soil amendments when installing new landscaping. Older neighborhoods may have mixed system types requiring careful assessment.
Aurora & East Denver
Variable water pressure across different elevations. Pressure regulators may be necessary to protect system components. Some areas have very hard water requiring more frequent valve maintenance.
When to Call a Professional
Some issues require professional diagnosis or specialized equipment:
- Underground leaks - May require leak detection equipment
- Wire locating - Finding buried wires and valve boxes requires specialized tools
- Backflow preventer testing - Many municipalities require annual testing by certified technicians
- Major repairs - Mainline breaks, valve replacements, and controller issues often benefit from professional expertise
- System design problems - If your system has persistent pressure or coverage issues, a professional assessment may identify design flaws
Schedule professional service for complex issues.
Frequently Asked Questions
How long should I run each zone?
This depends on head type, soil type, sun exposure, and plant material. A general starting point for clay soils:
- Rotors (large heads): 20-30 minutes per cycle
- Spray heads (pop-up): 8-12 minutes per cycle
- Use cycle-and-soak: split into two cycles with 30-60 minutes between
How often should I water in Denver?
Most established lawns need about 1 inch of water per week total (including rainfall). During peak summer, this typically means 2-3 watering days per week. New lawns and new plants need more frequent watering until established.
When should I winterize my sprinkler system?
Schedule winterization before the first hard freeze—typically late September through mid-November in the Denver area. Don’t wait for freezing weather; schedule early to ensure availability.
How do I know if my backflow preventer needs service?
Signs of backflow preventer issues include leaking from the device, failure to hold pressure, or difficulty with startup each spring. Most municipalities require annual testing by certified technicians.
Can I do my own sprinkler repairs?
Many minor repairs like replacing heads, adjusting nozzles, and cleaning valves are DIY-friendly. More complex repairs involving valves, wiring, or underground pipes often benefit from professional expertise and specialized tools.
Additional Resources
- Denver Water - Outdoor Watering Rules
- EPA WaterSense Program
- Irrigation Association
- Our FAQ Page
- Our Services
This guide is provided by 5280 Sprinklers, serving the Denver metro area since 2010. For professional assistance with your irrigation system, contact us or schedule service online.