What is the typical water pressure for a sprinkler system outside a home?
Not clear what the reason for the question is.  However, nominal water pressure for most residential homes is in the range of 40-70 psi (pounds per square inch).  It can vary due to the distance from the home to the water source (such as a water tower), how much water is being used by surrounding homes (higher usage will lower the pressure), the capacity of the water company to maintain pressure as usage varies, etc.  Most heating systems and water heaters require pressure reducing valves in order to make sure that the water pressure into those systems does not get too high which can cause damage.  In special situations, where the home is far from the water source and/or on high ground, a water pump may be necessary to maintain a reasonable pressure.  Getting back to your question, are you talking about a sprinkler system for watering a lawn or a sprinkler systems for putting out a fire.  In any case, both systems will have minimum pressure requirements based on how many sprinkler heads are in the system.  Too many heads would prevent either type of system from working properly.