At this writing I was looking for a black plastic vat. Now I believe the better way may be to dig a new well and have the laundry and toilets set up on the well and the rest set up on a the cistern we have. We have a 10,000 gallon cistern under the house now. Any good suggestions on who might be able to set that up for us.
You definitely need to separate the toilet/laundry from the rainwater supply. Then you can decide about the amount of rainwater storage. You should have some amount of well water storage too. so that you don't pump your well dry during heavy usage times.
Contact Frank Panton for excellent advice: 226-4195/ 622-5879