"Frank" wrote:

It's been over 30 years since I had a 2nd field installed at ~$1,000.

The minimum size requirements for a field have changed substantially over the
years. I don't think you will get a legal replacement field installed for $1000
these days.

It uses the same tank and goes to a junction box where fields are
easily switched as they are both gravity fed. Both are evaporation
fields but on 2nd one, perk was better. Even then, 2nd field came up
and I had to switch back to first after several years.

Two fields with a switch is great, if you can afford it and if there's room on
the lot for two fields.

You are lucky that your system has lasted this long. One contractor
explained to me that they do not perk as well over the years due to
salt build-up and need a couple of years of rain water draining
through them to restore them. With a 2nd switchable field, you should
never have to worry about septic again.

Salt? The amount of salt in effluent, even with a water softener is
insignificant. What happens to a field is that it plugs up with the natural
floating stuff that doesn't settle out in a tank. I'd be surprised to see rain
soaking through a field dealing with that, but maybe.