City engineers are now designing the major elements of a program that'll supply a third of San Diego's water in the next two decades.

It comes right down to being a high-tech conservation effort.

After five years of drought, people in this region shouldn't get complacent because they had such a rainy winter.

Forecasters are warning of more drought cycles ahead.

The need to maximize every drop available is what's turning on the flow of San Diego's "pure water program".

Years ago, clever headline writers got squeamish and coined the phrase "toilet to tap".

But scientists tell us our tap water is in no way more sanitary, odorless or tasteless than wastewater recycled through advanced purification processes.

Nearly 200 million gallons of "wastewater" is pumped into the Pacific here every day, after what's called "primary and tertiary" treatment.

So it's literally "wasted" -- useless.

Not ideal in drought-ridden, "arid" places like San Diego.

All but a fraction of our water is imported from the Colorado River and San Francisco Bay Delta.

Earthquakes could rupture pipelines from there.

By 2021, the city will start adding pure, recycled water into homes, and gear up to produce a third of San Diego's daily supply by 2035.

It's projected to be cheaper than the imported water we'll be getting by then -- much cheaper than desalinated.

"We're going to be capturing methane gas that currently is escaping from the Miramar landfill,” says Halla Razak, director of the city’s Public Utilities Dept.

In a recording session for NBC 7 ‘s “Politically Speaking” program, which will air Sunday at 5 p.m., Raza smiled as she enthused: “We're going to be creating energy and creating that water. So not only is it local, but it's also sustainable, because in fact we're going to be using 'green energy' to create it."

Construction on full-scale purification facilities will begin late next year.

Once the output goes into San Diego's system, people afraid to drink it can take showers in it, wash their cars and dogs, and water their lawns with it.