If it's from a washer, it's called grey water... bro
Couple problems using laundry water for irrigation...
Mainly the high sodium levels in most detergents (sodium sulfate, sodium carbonate, sodium silicate, sodium perborate) is not good for plants. Secondly, the perborate might raise the boron levels in the soil to toxic levels for boron-sensitive plants.
A septic system avoids the issue by distributing the "cleaned" effluent over a wide area, and rain is expected to leach out excess sodium. But all that's usually allowed over a leach field is grass, and there are some very salt tolerant grasses.
Couple problems using laundry water for irrigation...
Mainly the high sodium levels in most detergents (sodium sulfate, sodium carbonate, sodium silicate, sodium perborate) is not good for plants. Secondly, the perborate might raise the boron levels in the soil to toxic levels for boron-sensitive plants.
A septic system avoids the issue by distributing the "cleaned" effluent over a wide area, and rain is expected to leach out excess sodium. But all that's usually allowed over a leach field is grass, and there are some very salt tolerant grasses.