Not only are septic tanks environmentally friendly because it does not contaminate your water supply and it removes bacteria before the water is released into your soil. You can also recycle the water it releases to sustain various plant life nearby.
Septic tanks are also cost-effective, it costs much less than an underground sewer line and does not need to be maintained every month, you only provide maintenance once every 2 to 5 years. The septic tank is also quite durable and only needs to be repaired under harsh circumstances.