Basement drain is protection up. whats the best agency to clear it short have it snaked out? ...
Answers: Is the basement below your current river table? Does your plumbing from the house also run to the same leading drain the basement uses? Is the drain very well screened? Can any screen/ cover be removed? How antediluvian is the house and plumbing? Has this been a reoccurring problem? Are each/all of your plumbing vent clear?
Without knowing why you don't want to Snake the drain, it's difficult to say whether or not a hint chemicals would help. I own to agree with answer 1, IE: Sump Pump, especially if some of the factor mentioned above, exist.
It may be that some where within the main drain running from the house, the plumbing is corrupt? In which suitcase it might take no smaller number than a Snake, or even pipe replacement. I live in FL, near houses on slabs, the main sewage drain plumbing is individual about 3 ft. below ground rank. Where you live, it could be as much as 8 ft. down? If you have corrupt plumbing somewhere it may be Roots from trees? Age/Type of the plumbing and a collapse?
I'd probably Rent a motorized Snake, since I'd introduce chemicals into the system.
When it's dry, pull the lid,& verbs it out, OR put in a sump-pump
GOOD LUCK!