Been enjoying the pitter patter of rain drops on your roof?

Perhaps you’ve noticed the rain pooling on your driveway before gently cascading over the curb and into the gutter where it starts a fairly short journey to the San Joaquin River and the Delta.

Nature’s gentle tears of joy caressing the earth is the answer to prayers to weaken the drought. But it is also the start of another nightmare and it’s not flooding.

Northern San Joaquin Valley communities are in the process of complying with new discharge rules from storm run-off and even landscaping irrigation run-off on virtually all new development. It is part of California’s bid to comply with provisions of the Clean Water Act to reduce not only run-off from a particular site but also to assure what water does make its way off the site in question is clean.

And just so it’s perfectly clear, muddy run-off from rain hitting dirt and doing what has been part of the natural process on earth for the good part of 4 billion years isn’t acceptable. In other words the water that flows into a street storm drain and then into creeks, rivers, lakes, the Delta, and the ocean must be virtually clean. This isn’t just about making sure that things such as oil from people working on vehicles in their driveway doesn’t make it into the storm drain or the residue from fertilizers and pesticides. It’s to make sure only water and nothing else regardless of how benign it may be is carried or mixed with the run-off. But that’s not all. The goal is to contain as much run-off — preferably 100 percent — as possible on site.

It is why you will start seeing more and more French drains in Manteca and elsewhere. Basically they are sloping trenches filled with gravel or rock that also will often contain a perforated pipe with it. The tell-tale sign that there is a French drain below is by a collection of river rock typically clustered in long, narrow strips among grassy or landscaped areas.

Like most federal edicts, the basic premise makes sense. You don’t want foreign substances such as motor oil, chemicals, and such getting into nature’s intricate water system whether it’s a creek, river, lake, or the ocean. Nor do you want to deal with the accumulative impact of paving or covering more and more of the ground with impervious surfaces. In doing so, water from rain or other sources can’t soak into the ground and ultimately underground water tables. The more ground converted to imperable uses the greater the run-off which in turn makes flooding more and more common.

But what happens if such a strategy is too successful? In a normal water year it could significantly reduce water making its way to the Delta. Manteca by itself may not matter but if every community in the San Joaquin River water basin successfully complied it could have an impact on winter and spring flows into the Delta. And any drop-off in water flows into the Delta is always made up by raiding water stored for cities and farming in reservoirs.

Now couple capturing nearly 100 percent of all run-off from new development with another trend — the recycling of treated wastewater.

This may not seem like a big deal but it is.

Manteca-Lathrop discharges close to 10 million gallons of treated wastewater into the San Joaquin River every day. Tests show it is significantly cleaner than the water it joins in the river. It is why one of the favorite spots of anglers in the know is to cast a line near the city’s discharge point west of Oakwood Shores. Fish are lured to the area by the cleaner water.

What will happen to Delta water flows year round as cities such as Turlock, Manteca, Modesto and others move to repurpose treated wastewater for everything from domestic landscape irrigation to piping it to farmers in the region?

State law makes it clear that cities own their treated wastewater. It has allowed Stockton to sell their treated wastewater to farmers downstream.

But there’s one slight problem. Since few cities are currently doing what Stockton does, what happens if all of them that dump water into river basins that drain into the Delta do the same?

Currently that water not only flows through the Delta to help sustain the ecological system but it also ends up flowing into the San Francisco Bay or into the California Aqueduct via the pumps near Tracy to start the journey southward to quench the insatiable thirst of larger farms and Southland cities.

Take that water out of the equation along with storm run-off and even more demands will be placed on the already overtaxed and overcommitted reservoirs of the State Water Project and the federal Central Valley Project.

So the next time you pray for rain, you may also add a request for mortal water policies that don’t inflict more suffering on mankind than nature’s fury whether it is from torrential rains triggering flooding or extreme dry spells that bring us severe droughts.