My wife and I are having our first child and our considering cloth diapers. We live in an apartment complex with 10-15 units and all share the same two washing machines and two drying machines. We are wondering if washing cloth diapers in these machines could have a negative impact on the other tenants' (and our) clothes. I have not read this anywhere so I am guessing that it will not, but I wanted to get an explicit answer.
Nappies require a lot of washing and rinsing. You'll likely be doing a wash every other day. This increased time might be seen as problematic by other residents.
But I suspect your question is about poo: you don't put much poo into the machine.
Many cloth nappies use a biodegradable disposable liner which collects most poo, leaving the nappy much easier to clean. You'd probably be sluicing the nappies before washing them - some people recommend using the shower hose to remove solids. Or maybe you'd be soaking them.
You'd wash the nappy with a cold pre-wash, followed by a hot (at least 60 celsius) wash, followed by a good rinse. You'd use about half the normal amount of detergent, and make sure it wasn't a "biological" detergent. (the heat would kill most of the enzymes anyway, so there's no point in a biological detergent).
If your child is breast fed their poo will be water soluble and will wash away in the machine. If they're on solids or formula you may find their poo isn't water soluble. (Another reason for the hot wash and good rinse).
But you're likely to find that some people perceive a problem. They're likely to say it's unhygenic, or uses the machines too often. And most new parents report feeling a bit overwhelmed by the washing. So, if you're determined to use cloth nappies you might want to investigate a nappy washing service. These washing services tend to use less water and energy than home washing.
How do you deal with the poo?
Flush it! At each change, you flush any solid waste down the toilet. If you are using a flushable liner*, then simply flush poo, liner and all. If any waste has clung to the nappy - or you are using a washable liner - you may have to sluice this, too – it's not as difficult or distasteful as it sounds! You simply grip firmly onto a corner of the nappy or liner and rinse it in the toilet as it's flushing. Incidentally, if your flushable liner is merely wet, you can wash it in the machine with your nappies – I find they last fine for three or four washes before developing holes. If your water pressure is insufficient, and the toilet sluicing trick doesn't work, then rig up a shower spray (either use your shower, or use a rubber spray attachment over your bath taps), and use this to shower poo off the nappy into a dedicated bucket. This is very easy and effective. You then simply put your rinsed nappy into your storage bucket, and flush away the contents of the sluicing bucket.
TL;DR: No, there's no problem washing nappies in a communal washing machine. But other people may think there's a problem - and so that becomes the problem.
I would be most concerned about the added duration or use that your neighbors may not appreciate.
For my routine I have to pre-wash which takes about 1:10 in my machine, followed by a heavy wash with extra rinse which takes another 1:25 in the same machine.
After the wash, I also end up drying for two cycles or about 1:15 total dry as the brand I use can melt under higher heat.
In total, it can be upwards of 2:35 in the wash and 1:15 in the dry(if I hear the end of cycle alarms!) which could end up delaying the next user quite a bit of time if they want to use either. Keep in mind most brands recommend a daily wash routine as well!