| 100% | SEWERS | 6 | Underground channels |
| 99% | SEWER | 5 | Underground channel |
| 99% | METROS | 6 | Some undergrounds |
| 97% | AORTAS | 6 | Some circulation channels |
| 97% | METROS | 6 | Some underground networks |
| 95% | FREESTATES | 10 | Some Underground Railroad destinations |
| 95% | ORE | 3 | Some underground rock bands? |
| 95% | SEWER | 5 | Underground channel for waste |
| 91% | SEWER | 5 | Underground channel that carries waste material |
| 90% | SPELUNK | 7 | Do some underground exploring |
| 89% | SEWER | 5 | Underground channel where the Ninja Turtles live |
| 88% | ALTCOMEDY | 9 | Genre for some underground sketches? |
| 88% | SEWER | 5 | Underground waste channel |
| 86% | UHF | 3 | Some TV channels (abbr.) |
| 86% | RRS | 3 | Some are underground: Abbr. |
| 85% | SEWER | 5 | Underground waste disposal channel |
| 85% | BIOS | 4 | Some History channel fare |
| 82% | BASEMENTPARTY | 13 | Where you might dance to some underground music? |
| 81% | SEWERS | 6 | Sanitation channels, underground drainage |
| 81% | SUBWAYSTOP | 10 | Where some go underground |
| 81% | ESPN | 4 | Channel that hosts some WNBA games |
| 79% | IRONMINES | 9 | Underground venues for some heavy-metal bands? |
| 79% | CSPAN | 5 | Channel for some live D.C. action |
| 77% | GASLINES | 8 | Underground pipes leading to some stoves (2 wds.) |
| 74% | TCM | 3 | Channel on which to see some b&w films |
| 74% | UHF | 3 | Like some TV channels, briefly |
| 68% | SEWER | 5 | Underground waste disposal channel that served as home to the monster Pennywise |
| 66% | WARTIME | 7 | Backdrop for some History Channel programming |
| 66% | BULB | 4 | Underground storage part that's present in some garden plants (e.g. Onion) |
| 54% | TED | 3 | Turner of channels |