FT. LAUDERDALE (CBSMiami.com) – If you want to water your lawn, you need to check the calendar in parts of South Florida. New water restrictions went into effect Saturday in Broward and Palm Beach counties, at least on paper, but it’s not certain who will be enforcing them.

CBSMIAMI.com Guide To Water Restrictions

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The new watering rules involve cutbacks for homeowners, agriculture and golf courses as a continued drought has water managers worried about water supplies in advance of the rainy season.

Under the new rules, golf courses, nurseries and agriculture in Broward and Palm Beach counties must reduce water use 15 percent.  Watering is allowed just twice a week, a change for Palm Beach County and the city of Ft. Lauderdale, which had been allowing three-times-a-week watering.

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The new rules make twice-a-week landscape watering the maximum allowed across South Florida. The rest of Broward and Miami-Dade counties already limit landscape watering to twice a week.

Under the rules that took effect Saturday, homes and businesses with addresses ending in odd numbers can water on Wednesdays and Saturdays. Addresses ending in even numbers can water on Thursdays and Sundays.

Even on days when you are allowed to water, it’s against the rules to water during the hottest parts of the day, from 10 a.m. until 4 p.m., when evaporation would be the greatest.

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If that sounds harsh, some areas of South Florida are already under tougher watering rules. The cities of Lake Worth and Hallandale Beach limit watering to a single day.