Site and Water-Supply Assessment
Site and water-supply assessment establishes what the irrigation system can support. We measure static and operating pressure, confirm available flow, locate the irrigation connection and shutoff, and review slopes, soil, sun exposure, planting types, walkways, and structures.
The assessment also maps practical pipe routes and valve-box locations. Existing trees, hardscape, utilities, drainage features, and future landscape plans affect where components can be installed and accessed. Accurate field information prevents oversized zones, poor head spacing, and unnecessary trenching.
Custom Irrigation Design
Custom irrigation design groups areas with similar watering needs. Turf spray, long-radius rotors, shrubs, and drip irrigation should not share a zone when their application rates and run times differ. Separating these hydrozones gives the controller useful control over each landscape area.
The design accounts for:
- Available pressure and gallons per minute
- Pipe diameter, route length, and elevation change
- Sprinkler radius, arc, and head-to-head spacing
- Nozzle flow and matched precipitation rates
- Drip filtration and pressure regulation
- Valve size and accessible valve-box placement
- Controller station capacity and future expansion
- Rain or weather sensor placement
- Approved backflow protection for the connection
Hydraulic calculations keep total zone demand within the supply. Proper spacing distributes water evenly instead of relying on longer run times to compensate for dry gaps.
Irrigation Installation Process
Irrigation installation converts the plan into a serviceable system. Seattle Plumbers marks routes, trenches with attention to known utilities and landscape features, and installs the mainline, lateral piping, valves, fittings, heads, drip components, control wire, and waterproof splices.
We set sprinkler bodies near finished grade, align them away from paving and structures, and provide accessible valve boxes. Pipes are flushed before nozzles and small passages return to service. Open connections remain protected from soil so debris does not reach diaphragms, filters, or emitters.
Installation steps typically include:
- Confirming the layout and water connection
- Installing the shutoff and required backflow protection
- Routing mainline and zone piping
- Setting valves, heads, drip equipment, and control wire
- Flushing and pressure-testing piping
- Programming the controller and sensors
- Adjusting each zone under normal operating pressure
Backflow Protection and Seattle Requirements
Backflow protection and Seattle requirements apply where irrigation connects to potable water. Seattle Public Utilities requires actual or potential cross-connections to be eliminated or protected with approved equipment. The correct assembly depends on the installation and hazard, especially when pumps or chemical addition are involved.
New mechanical backflow assemblies must be installed in an approved manner and tested by a Washington State certified Backflow Assembly Tester before use. Installed assemblies require annual certified testing and testing after repair or replacement. We plan for accessible shutoffs, testing clearance, drainage, and required inspection rather than treating the assembly as an afterthought.
Permit and inspection needs can vary with the connection, backflow work, electrical work, and project scope. We identify the applicable coordination points before construction and keep required components accessible for inspection.
System Startup and Owner Orientation
System startup proves that the installation works as designed. We pressurize the piping gradually, inspect joints and valve boxes, run every zone, and confirm sprinkler extension, rotor movement, drip flow, valve closure, and controller response.
We then program an initial watering schedule based on zone type and seasonal conditions. You receive a clear explanation of the shutoff, controller, manual-run function, sensor bypass, zone map, and common maintenance needs. Final adjustments direct water toward plants and away from walls, windows, sidewalks, and streets.
Frequently Asked Questions
How many irrigation zones will my property need?
Zone count depends on available flow, landscape size, head and emitter demand, slopes, and plant groups. We calculate demand rather than assigning zones by square footage alone.
Can sprinklers and drip irrigation share one zone?
They usually perform better on separate zones because they apply water at different rates and need different run times, filtration, and pressure.
Will a new irrigation system need backflow protection?
Irrigation connections to potable water require approved protection appropriate to the installation. Seattle Public Utilities or the plumbing authority determines specific requirements.
Can the controller allow future expansion?
Yes. Selecting extra station capacity and planning accessible routes can make later landscape changes easier, subject to the available water supply.
Schedule Irrigation Installation in Seattle
Schedule Irrigation System Installation with Seattle Plumbers for measured design, orderly construction, and complete startup testing. We build the system around your water supply and landscape so every zone has a clear purpose and serviceable components.