The chlorine levels will be higher than what you need, but that one-time shock won't be harmful to the pool. If you will be gone for several weeks or months, you'll need to hire someone to do the pool maintenance for you, including shocking the pool once a week.
So if you have to leave it running for a week it shouldn't make a big dent in the electric bill. Having to spend the money on getting the pool back in shape will probably cost more than leaving it on anyway. I would make sure you fill the pool water as high as you can though since you will be gone for a week.
I think the answer to your question is about 3-6 days. The problem is that the chlorine that you need to keep the bacteria in check is used up more quickly as the temperature rises, the activity increases, and as sweat and other body stuff is put into the pool.
So make sure your filter pump is either on a timer (daytime cycles are best because that's when water is warmest and most likely to turn bad) for 12 hours daily or find a trusted neighbor or friend who can turn your pool pump on and off while you're gone.
As long as your pool has enough water in it to counteract the water pressure that's outside the pool, you don't have a problem. But if you empty the pool, even concrete pools, you risk serious issues, including damaging the vinyl liner, cracking concrete sides, and the pool literally popping out of the ground.
First, if the draining is done at the wrong time or under the wrong conditions, you can actually risk damaging your pool structure and liner. All the water from your pool needs to go somewhere when it's drained, and that usually means the ground.
A pool can only be safe for swimming without a pump for a few days and a maximum of one week. The definite number of days the pool will be safe will also depend on the temperatures of the water, the weather at that particular time, the level of chlorine, and how clean the pool was before the pump stopped functioning.
Add Extra Chlorine
Since you'll be away, you'll need to put extra chlorine in the pool to cover your absence. Put an extra tab in the skinner or turn up the automatic chlorinator a few notches. Shock the pool twice as hard as you normally would.
Every pool must turn over at least once a day, so most pool pumps should run approximately 8 hours a day. But here's the thing: you don't have to run your pool pump consecutively. You can choose to run it for three hours in the morning before you leave for work and another 5 hours in the evening.
It takes a lot of chemicals to make pool water safe for swimming. Untreated water can accumulate harmful Escherichia coli and Salmonella bacteria and protozoans such as Cryptosporidium parvum and Giardia lamblia.
Dirty water becomes a breeding ground for parasites, mold, and bacterial. The bacteria keep growing if the water is not wiped. Within 48 hours, you will see that the entire surface of the pool is covered with mold. As mentioned above, stagnant water attracts rodents and insects.
The Bottom Line about Pools and Chlorine
As mentioned above, you could probably swim in a pool without chlorine without any major health issues. However, long-term use of a pool lacking chlorinated H2O could make you sick or, at the very least, contribute to rashes and other types of skin irritation.
Depending on the size of your pool, we still recommend the pump run 8-10 hours per day during the hottest summer months and at least 6 hours per day during the winter months.
If you don't, the pool will have decreased water flow which means reduced filtration and ultimately, the dreaded algae bloom. The pump basket should be cleared out weekly and even more frequently during the fall and spring when there is more debris in the pool.
Covering your pool makes it difficult for algae to grow. It will be well worth coming back to a clean pool. If you do not own a pool cover yet, this would be a perfect time to buy since you will still need one once the colder months come around.
It may be cheaper to run the pump at night, but honestly you should run it 1 hour a day per 10 degrees of temperature at least, and it should be during the day. Running the pump at night should only be when you are doing a major chemical treatment such as algae clean-up.
A pool isn't designed to be stagnant during the warm months of the year, and pool covers deteriorate faster in strong summer sunlight. Leaving the pool closed all summer is a guaranteed way to end up with a green, smelly mess and permanent stains or damage to the pool surfaces.
Your pool can keep running for a few days with no problems while without a pump. However, know that a standard pool needs a pool running for at least once in 24 hours, or you might notice an algae bloom. So, it's best to have your pump ready as soon as possible.
One of the most significant consumers of energy in homes with swimming pools are pool pumps, which keep pools clean by circulating water through filters. Pool pumps can consume 3,000 to over 5,000 kWh per year.
It's best to run your pool pump during the day
Not only does sunlight give fuel for algae to grow, it also destroys your pool chlorine and this is why you should always run your pool during the day!
Filling your pool with dirt is the fastest and most affordable way to get rid of a pool because there's no need to remove your concrete or metal shell. This saves on both labor and hauling costs. However, filling a pool with dirt is still a delicate process that requires careful preparation, drainage, and demolition.
You can turn your swimming pool into a koi pond. It can take weeks but it can be worth it to see your yard go from looking man-made to looking like a natural slice of paradise.
Pool industry experts recommend you drain your pool and refill it every five to seven years. No two pools are alike, so there is no set number at which you must drain your pool.