While it is ideal to install a sprinkler system in your yard before you have planted gror flowers, it is possible to install one in an existing yard. If this is the case, you will need to account for the cost of reseeding and repair into the cost of the sprinkler system installation..Learn about the factors that impact the price of a sprinkler system and what sprinklers cost Sprinkler System Price Estimates. to install the system, .Sprinkler System Pricing and Installation Cost Checklist. Get at least estimates before hiring a Sprinkler System contractor estimates are typi.y free, unless it’s a service for a repair..The homewyse Sprinkler System cost estimates do not include costs for excavation, demolition and removal of existing paving or hardscape. Sprinkler System installation costs vary considerably by location. For an accurate estimate in your area, enter your zip code in the calculator above..