Natural gas is usually high pressure in the main natural gas lines before it reaches the towns and cities they serve.
Then once the natural gas gets to homes and businesses the natural gas pressure is lowered some to make it safe to enter homes and businesses.
A residential natural gas line coming into your home after your gas meter should be between 0.25 psi and 1 or 2 PSI.
The natural gas in the main pipeline leading to your meter could be between a 1/4 psi to 60 psi, depending on the number of homes or businesses served by that same natural gas line.
After the gas line reaches the home the natural gas is lowered using a pressure regulator so that you get the optimal and safe natural gas pressure to your home.
Too much pressure and your appliances could explode and to little pressure on the natural gas line then your natural gas appliances may not work properly.
The most common natural gas pressure for appliances such as water heater, furnace, stove etc is around 7 inches of water column (WC) or re-stating this in equivalent measure, that's 14.9 millibars or 1743 Pascals or Pa, or about 0.25 psi (pounds per square inch) or about 4 ounces.