| Business | Phone |
| Willow Pass 76 2380 Willow Pass Rd, Concord 94520 | (925) 685-7151 |
| Aaaaa Smog Center 2134 Market St, Concord 94520 | (925) 687-7664 |
| Auto Smog 2241 Monument Blvd, Concord 94520 | (925) 677-2180 |
| Bay Area Smog 2575 Monument Blvd # F, Concord 94520 | (925) 689-2312 |
| J & E Auto Repair 2575 Monument Blvd # J, Concord 94520 | (925) 685-6905 |
| Save On Smogs 1930 Arnold Industrial Pl, Concord 94520 | (925) 459-8668 |
| Smog Shop 1122 Erickson Rd, Concord 94520 | (925) 686-2900 |