What are the range of pressure values we receive from an ultrasonic sensor?
tl;dr: First determine your static pressure, double the value, then buy a microfone/hydrophone or pressure sensor that has relative measurement/pressure equalization for this range. Keep frequency range in mind.

The pressure you will be measuring consists of two components: Static pressure and ultrasound wave.
The static pressure depends on the weather (in air) and height/depth (especially in water). Normal air pressure at sea level is between 70 and 100 kPa. The maximum pressure the ultrasound wave can generate is double this pressure, because it consists of a sinusodial waveform (or multiples of these) which swings symmetrically around the baseline/static pressure. So an ultrasound wave can at the extremes go down to absolute vacuum in the negative halfwave and double the static pressure in the positive halfwave.

This does not mean your sensor needs to measure the static pressure. In fact, every ultrasound receiver has pressure equalization on the backside, so it is not burdened by static pressure. Most pressure sensors also have this by design or as an option. It takes away the static pressure from the measurement but the static pressure still defines the maximum possible pressure of the ultrasound wave as you can never go lower than absolute vacuum.

Also keep in mind that the term pressure sensors is often used for low bandwidth, so they will maybe measure nothing at the ultrasound frequency. High bandwidth pressure sensors would often be microfone/hydrophone or ultrasound receiver. Just keep the frequency range in mind when looking for specs.