Wee had a septic tank for years but it never beeped. Not sure why yours does.
Depending on what sort of septic tank it is, there are many different things about them. You need to know what sort it is, whether it uses a pump and if so what for, and any other relevant maintenance issues.
You shouldn't need a professional service for a lot of basic septic tank stuff. Often it's just a matter of know your tank and give it what it needs at the right time.
Different kinds of tanks -
1) Absorption - these will pretty much look after themselves all the time, needing very little done unless something goes wrong. Septic waste (from toilets) goes into the main septic tank where it is digested. Grey water (from sinks, washing, showers etc) should go into absorption trenches, which is where the digested liquid from the septic should also go. The sludge is what is left in the tank and a healthy tank generally digests so well that it may not need pumping out for decades, literally. We would often go ten years between pumpouts, and that is with 6 of us.
To look after an absorption tank, you do need to keep the tank alive (we used to buy a product called Actizyme, rather than just flushing yeast. This is a specialist product, not expensive.We'd throw down a handful of granules down the toilet once a week or so). If anyone in the family is taking antibiotics, you need to use a lot more of the Actizyme stuff because antibiotics will go through your body into the toilet and risk killing the bacteria in the septic tank. This will rapidly fill the tank with sludge and can block it fast. If the sludge overflows into your trenches it can be expensive and smelly.
2) a reticulation/chlorination system. These have various brand names and frankly, are very touchy to use. Some people love them, I hate them. These are more complex than a standard absorption system. Instead of absorption trenches, this type of reticulation system still has the main sludge tank, but the grey water plus digested liquid effluent gets sprayed or pumped onto an area of ground set aside for the purpose. In my experience this happens at regular timed intervals regardless of the weather and the state of rainfall. I've seen properties which were already waterlogged form floods, which then had the regular grey water being reticulated to add to this load. This stuff being sprayed/pumped was generally chlorinated first, to make sure it was bacteriologically safe.
3) pump-out system. THis is little more than a larger version of a pit toilet. It fills up over time and you pay someone to come and pump it out. In the meantime there could be some digestion in the tank, but generally there is nowhere for the digested liquid to go and be used.
I loved our absoption tank, I felt it was putting the nutrients back into our soil and we were dealing with our own waste on site. The biggest problem we had was when we changed to a front-loader washing machine which meant our grey water was less in volume and more concentrated - Aussie native plants don't like phosphates and we lost some lovely trees which were just downstream from our absorption trenches.
Variations on those above three - you might have a pump system that pumps to the trenches (type 1) or to a reticulation area after chlorination (type 2). There can be different levels of sophistication which can complicate the picture. When they finally sewered our villlage, some people were allowed to keep their septic tanks (we tried but it was going to be too expensive). Some had no choice, their location meant it was going to be too awkward to connect to the sewer. A lot that connected found they still need pumps because their property is below the level of the sewerage mains and they have to pump up to the mains. This requires regular maintenance and careful service, you don't want to find everything backing up.
Serious suggestion - if you're concerned, call a plumber for an opinion. You may not have a big problem, it could be quite a simple issue (a battery needing changing in a smoke detector, kind of problem).
Can you open up the inspection port and have a look? At the very least, it should show you how full your tank is, how healthy it is etc. There should be some useful info on line to tell you how a healthy tank should look. I won't go into too much detail here, I don't want to put you off.
When we first moved to this village, husband & I rented. The place we were renting had septic tank problems, husband & I had a go at trying to help fix it. I remember guddling around with a long pole and checking out the quality of the sludge, to find that a previous tenant had apparently been flushing disposable nappies into the septic system (not smart!) and the plastic liner (which you also get with sanitary napkins) had accumulated, NOT digested (of course) and were blocking various pipes etc.
Before the village had the sewer connected, I was on a committee which travelled around learning about septics, sewerage etc and we were shown how sewerage stations worked. Never again will I flush anything down that is likely to find itself stranded on the sieves they have to use! All those years of reading the packaging of various sanitary protection which says, "easily flushable" - never again. Cotton buds too, surgical swabs, etc. In some countries they don't even put toilet paper down the loo. In our house, we don't put anything more than toilet paper down the loo, with the usual human bodily waste. Everything else goes in the rubbish. It's where it ends up anyway, why should someone else have the job of having to filter it all out after it's been made all mucky?
So I can't help any more than that, sorry. But do get an opinion form a plumber before you go straight in to organise a pump-out - you probably DO need a pumpout now, but you probably would benefit from a professional opinion based on how the tank looks now. They can help you know what went wrong (if anything) and what to do next time.
Marg