Medical bills are a huge problem among working Americans and seniors alike. More than 25% of U.S. adults struggle to keep up with their healthcare expenses, according to the Kaiser Family Foundation, and that includes folks who have insurance. The problem is so bad, in fact, that medical debt is the No. 1 source of personal bankruptcy filings in the country.

Now there are several tactics we can all employ to save money on medical bills, like taking care of ourselves and addressing health issues before they worsen into major problems. But sometimes, despite our vigilance, we inevitably wind up in the emergency room for reasons outside our control.

The word Emergency on a red sign over a hospital emergency entrance.

IMAGE SOURCE: GETTY IMAGES.

Unfortunately, that's when the bills can really start to pile up. In 2016, ER visit spending climbed to $1,917, on average, according to the Health Care Cost Institute, which analyzed the spending of nearly 40 million Americans with employer-sponsored health coverage. That figure represents more than a 31% increase from just four years prior. It also explains why so many Americans -- even insured ones -- land in such a deep financial hole when unplanned medical issues arise.

Why are ERs so expensive?

Emergency rooms have never been cheap, but what's with the sudden spike in cost? There are several factors at play. For one thing, ERs are seeing a larger number of patients with more extreme health issues, and they base their facility fee -- the fee you're charged for walking in the door -- on the severity of the conditions they're treating. Meanwhile, with urgent-care facilities popping up all over the country, mildly ill or injured patients are increasingly opting for walk-in clinics over ERs for seemingly minor issues. As such, the patients who do land in the ER tend to be the most critical ones.

Furthermore, ERs are getting fancier by way of equipment and technology. CT and MRI machines cost money, and patients will often undergo testing while already in the ER rather than wait to follow up with local labs or doctors. As such, they're paying a premium for that convenience.

Avoiding a whopper ER bill

Clearly, we can't prevent accidents that might land us in the ER, but we can, collectively, be smarter about when we run to the emergency room. If you're dealing with a non-life-threatening medical problem, like an ankle you aren't sure is broken, it almost always pays to go to an urgent-care clinic over the ER. You're likely to have a shorter wait and a much lower copay under your insurance plan.

If you have no choice but to seek out ER care, pay attention to the bills you receive afterward and aim to negotiate them down. A study last year found that hospitals mark up ER services by an average of 340% more than what Medicare allows for. If your bills are catastrophic, talk to the hospital about working out an arrangement. At the very least, you might manage to get on a no- or low-interest payment plan, even if you don't manage to get your actual costs reduced.

Finally, make sure the bills you're looking at reflect the services you received. Billing code errors happen all the time, and a simple mistake could pad your bill by several thousand dollars. If you don't understand what you're being billed for, call and ask the question -- it could end up making an otherwise whopping expense just a bit more manageable.

The Motley Fool has a disclosure policy.