Play particle effect on water trigger

using UnityEngine;

//Note: The water object must have a BoxCollider attached to it with the "Is Trigger" box is checked.
//The water object should also be on the "Water" layer.
public class WaterEntryEffect : MonoBehaviour
{
    [Header("Leave this object unparented, so it can be positioned freely")]
    // Effect should have simulation space set to "World" so it can be teleported freely
    public ParticleSystem entryEffect;

    void OnTriggerEnter(Collider collider)
    {
        //Trigger if other object is on the "Water" layer
        if (collider.gameObject.layer == 4)
        {
            // Position effect at current collision point and play
            entryEffect.transform.position = this.transform.position;
            entryEffect.Play();
        }
    }
}