The drought continues

It is rather normal for our area to get unreliable rainfall during the dry season, however, since November 1st, we're 12 inches below "normal". Since the start of this year, we're more than 4 inches below normal. It is showing, not just on my own lawn, but everywhere. A drought index of 500 is already high, most areas around Palm Beach County and Martin County are in the mid 600's, there are even some areas that are over 700 (including some wildlife refuge areas). It makes for a very flammable situation, brush fires are sprouting up everywhere. Every so often the sky darkens and I look longingly for some rain, but then the wind blows it all away and nothing happens. To top it all, my 10 year old sprinkling system is acting out also, at least two heads need to be replaced - yesterday I decided to water the grass adjacent to the patio as its really looking terrible, so one of the heads decided to stop turning, when I tried to make it turn, the whole head came off and no matter what I tried, I couldn't get it back again - the solenoid valve is also not functioning correctly, causing the system to stay on one station, so I have to manually water station by station and remember to turn the controller off lest I wake up on a Saturday to find one station drenched and the rest dry as dust.

I've been contemplating getting some rain barrels, but they're normally only 55 gallons, some are a little larger. But with our sporadic rainfall in the dry season, its not even a drop in the bucket for me. Also the cost of these barrels are prohibitive.

I've been looking at building my own water storage tank, using the ferro cement technique - a google search for "ferro cement tank" brings up many matches, detailing how this can be done easily. The only problem is that the tank will really have to look decent in order not to incur the wrath of neighbours and HOA. Furthermore, I don't know if there are any permits needed. The other problem is that it would have to hold a substantial amount to make it worthwhile.