Water protection levels 1 through 4 define resistance to low-velocity water, ranging from simple vertical dripping (IPX1) to full 360-degree splashing (IPX4).

The second characteristic numeral indicates protection against harmful effects due to water ingress, tested with fresh water. Lower levels focus on drops and low-pressure projection.

• IPX1 (Vertically falling water drops): The enclosure is placed on a turntable rotating at 1 r/min and tested under a drip box (Figure 3). The required water flow rate is $0.5_{-0}^{+1}$ mm/min. The test duration is 10 minutes, and vertically falling drops must have no harmful effects.
• IPX2 (Vertically falling water drops when tilted up to 15°): The same drip box is used, but the enclosure is tested in four fixed positions, tilted 15° on either side of the vertical in two mutually perpendicular planes. The flow rate is slightly adjusted to $0.5_{-0}^{+3}$ mm/min, and the duration is 2.5 minutes for each position (10 minutes total).
• IPX3 (Spraying water): Water is sprayed at an angle up to 60° on either side of the vertical. This test uses either an oscillating tube (Figure 4) oscillating through 120° for 10 minutes, or a hand-held spray nozzle (Figure 5) with the counterbalanced shield in place. The minimum test duration with the nozzle is 5 minutes.
• IPX4 (Splashing water): Water is splashed against the enclosure from any direction (360°). If using the oscillating tube, the tube has spray holes over the full 180° arc and oscillates through almost 360°. If using the spray nozzle, the counterbalanced shield is removed, and the enclosure is sprayed from all practicable directions. The duration is 1 minute per square meter of surface area, with a minimum of 5 minutes.

For all these tests, the acceptance condition is that the water ingress shall not be sufficient to interfere with the correct operation of the equipment or impair safety. The designation up to and including IPX6 implies compliance with all lower characteristic numerals.