| Business | Phone |
| Archer Engineering 15205 Lake Mathews Dr, Perris 92570 | (951) 940-1826 |
| Ault Engineering Inc 21151 Nandina Ave, Perris 92570 | (951) 443-1200 |
| Perris Engineering 1051 Davids Rd, Perris 92571 | (951) 657-2822 |
| Tri-Lake Consultants Inc 170 Wilkerson Ave # D, Perris 92570 | (951) 943-6504 |